You’re only young once and there’s a lot more to life.
FWIW the OP has not been back since the day this was posted.
I started college at 14 so I have a pretty good idea of what you’re feeling since I’ve experienced it firsthand. I think it’s great to be enthusiastic about school and learning. One thing that I’ve seen the last 2 years in college is a lot of people who don’t have any motivation or excitement for learning. Hold onto that. If it makes you happy, theres nothing wrong with it. Only you can decide how you spend your time, and to be spending your time on school is definitely not an issue. But also know when it’s time to step back. If you know you enjoy studying but you also get tired or sometimes too stressed, take a break, do something else, and then come back to it. Self care is really important. The most important key to staying motivated to study and excel and enjoy it, is to not overdo anything to the point where you lose interest. Everything in moderation. Set aside time for new hobbies. Colleges care about extra curriculars too 
I think that middle school is a great time to (1) develop good work habits that will pay off in high school and college, and (2) start developing as a person. Find out what excites you, and try to pursue it. Think about how you want to develop as a person. Do things because they interest you and make you happy, not because they are perceived as a means to an end.
I have an 11 year old son who will be entering 7th grade. He is highly gifted and academically advanced, but I try to shield him from thinking about college at all. I’ve told him to keep his grades up and do well academically, and he will end up somewhere good, and not to worry about it. He started many ECs when he was 5, and has stuck with a number of them, so he is quite advanced in several areas - high school level or above. His combination of activities - all things the he loves and has chosen - make him stand out, and I suspect that if he keeps these up he will have no problem standing out for application purposes. But that’s entirely irrelevant. My son does his ECs for enrichment and because he loves them, with absolutely no consideration to how they might impact his future college application process; if he somehow theoretically discovered that they would have no bearing on that process, or even a negative one, I think he would still choose to do them. And if he decides to drop many of them and go in an entirely different direction (unlikely IMO, but certainly possible), they will still have contributed immeasurably to his development as a person, and been well worth his time and effort.
We sometimes forget that college is not the endpoint in life, it’s just one stop on the road. Finding a good college fit is important, but it’s not everything; developing as a person in a way that will lead to a happy and fulfilling life - with college just one step on the path - should be the overall goal.