It's not too late, but as @twogirls ls said, you won't be applying next year. D1 only decided her senior year of college she wanted to try for med school. She's now a physician, but it took her 3 years after her college graduation to get her pre-reqs & ECs done before she applied.
You don't need to change your major. (D1 & D2 both went to med school. They had classmates with majors that include forestry, music performance, theology, Spanish and business, as well as the more typical science/engineering majors.)
However, med schools do have a defined set of required coursework you must take to be considered for admission:
2 semester biology w/lab
2 semesters general chem w/ labs
2 semesters organic chem w/ labs
1 semester biochem
2 semesters physics w/labs
2 semesters college-level math, one of which needs to be statistics or biostatistics
2 semesters college composition
1 semester psychology (required at some schools, tested on the MCAT)
1 semester sociology (required at some schools, tested on the MCAT)
Generally speaking, med school admission committees strongly prefer that pre-reqs be taken at a 4 year college, not at a CC. (Although osteopathic med schools are more lenient about this.)
You could delay your graduation and take your pre-reqs at your current college or you could graduate and do a post-bacc program for career-changers. Post baccs range a great deal in price and vary from very structured to a piecemeal do-it-yourself option. Formal post-bacc tend to be very expensive ($60K or more). There is no financial aid available except for loans to pay for a post-bacc program.
Besides having the right coursework, med schools are looking for people who know what they're getting into and have demonstrated the qualities they find necessary to be successful doctor. There are numerous expected ECs that successful med school applicants have-- community service with vulnerable and underserved populations; clinical volunteering; physician shadowing; demonstrated leadership; and for some schools (particularly at highly ranked, research oriented schools) significant bench or clinical research.
If you have never done any clinical volunteering or physician shadowing, I would suggest doing both is a necessary first step before you invest your time, effort & money into becoming a pre-med. You need to know if you want to spend the next 10 years of your life preparing to become a physician.
One more thing you need to consider before committing to this path-- every year 60% of medical school applicants do not get an acceptance to medical school.
Make sure you have a Plan B.
ETA: If you only want to be surgeon and nothing else. please don't go become a pre-med. The vast majority of med students end up in one of the primary care specialties (family medicine, general internal medicine, pediatrics, OB/GYN or psychiatry.) While general surgery isn't especially competitive, there are zero guarantees that you will qualify for or match into a surgical residency.
Only consider med school if you are willing to go into it with an open mind.
Also, what is your current GPA?
Med school admissions used GPA as a screener when considering applicants. Last year the average GPA for successful applicants was 3.7+ for allopathic med school applicants and 3.58 for osteopathic med school applicants.
I think it's going to depend on how serious the relationship is. There is a difference between serious and long-term.
A serious relationship is one that is definitely heading toward marriage/commitment. Long-term is one that has lasted several years, but isn't progressing. Long term is comfortable and familiar, but not necessarily serious.
Both my daughters are/were med students. Medical students are required to complete a residency in order to become practicing physicians, but they have very little control over where they are placed for residency. (It's done by a computer program.) Going into 4th year of med school and residency placement both were/are involved in long term relationships and in D1's case, a very serious relationships. D1 selected her potential residency sites jointly with her BF and with his ability to find employment after a move in mind. She was also talking about a spring wedding after graduation. But when it came down to her actually interviewing and moving, her BF chose to break if off. She relocated to the opposite coast--and reconnected with a friend whom she had briefly dated (one date!) 6 years earlier when they were both still in college. D1 and the old friend were married a year later. (BTW, I consider my new SIL a major upgrade over the her previous BF. Her husband completely rearranged his life to be with D1--including moving from another country/continent to be with my daughter while she finishes her studies, while her ex wouldn't even consider leaving town to move to another part of the state for her. That's love.)
I guess what I'm saying is life throws everyone a curve ball now & then. Change can be scary, but change is part of life and growth. Change can be painful (D1 was devastated by her ex's defection), but change can also be beneficial and life affirming too. If the relationship with your GF is meant to last, it will.
I think you should be proud of you GF's accomplishment and encourage her to take the new position. (It's too easy to breed resentment between you if you don't.) You need to discuss your feelings with your GF. Let her know you're anxious about her move and find out what she expects from the relationship.
You can major in anything and still go to med school so long as you complete the med school pre-reqs.
If time is a crunch item--and it is usually is for athletes-- choose a field you find interesting but has a large overlap with those pre med requirements. Biology, neuroscience, BME, chemistry, chem engineering--these majors typically have the largest overlap.
Not particularly helpful, but D2's high school science lab partner for 3 years went to Stanford as a recruited athlete in track & field, majored in BME, qualified for & went to the Olympic trials in his sport (didn't make the final Olympic team though), had a pro sponsorship contract for a year after college & competed professionally. He still managed to keep his GPA in med school worthy range (3.7+). He and D2 are now classmates again--this time at the same med school where they're both MS4s. (And where they're both in the running for class valedictorian.)
ETA: Because the lab partner had summer training and other commitments (he had summer sponsorship contracts that had required appearances and sports camp teaching), he was not able to take any summer classes. And because track & field has both fall & spring seasons (with the co-comittant travel & training), he was not able to save his tougher classes for a particular term, nor was he able to take an overload of courses. This meant that if a class wasn't already part of the graduation requirements for his major, he wasn't able to take it. This meant that he would have been completely unable to take his pre-med requirements if they weren't already part of his major. This is something to keep in mind when choosing your major--especially if your sport is multi season or the season overlaps both fall & spring terms.
UNM has good physics & EE depts (ask me about the physics dept--D1 is a UNM physics grad). NM is home to 2 National Research Labs (Sandia and Los Alamos) and 2 military research labs (Phillips Air Force Research Lab in Albuquerque and White Sands in Alamogordo). Plus Intel has major facility in town. Lots of internship possibilities.
Another possibility would be NM Tech--small engineering college in Socorro, NM (which shares its campus and facilities with National Radio Astronomy Observatory if you're into astronomy or astrophysics. The Tech students have their own student-run radio telescope.) Tech offers OOS tuition remission (Tech's tuition, fees plus room & board ~$14K annually) and several levels of scholarships. You'd qualify for the Presidential Scholarship which is $4K annually, putting your costs at about $10/year.