It might be easier to give good advice if we knew the names of the schools that you are considering, including the affordable alternatives. However…
“med school is a big maybe”
The classic advice (which I agree with) is that there are many schools with very good premed programs, premed is going to be academically very demanding at any “top 100” university, and you should attend a university where you can maintain an high GPA and keep some money in the bank for medical school.
“CS is a different path entirely”
True. However, in CS the “prestige” of the university does not matter much, and most of the top 20 universities for CS are not in the Ivy League.
In my opinion, you would need to have a very good reason, or very wealthy parents (or both), to spend $300,000 for four years of undergraduate education.