or I should wait to get a "stable" income source so I can get people to do the programming for me ... as much as I don't want to wait for almost a decade (medical school is hella long)
Your idea will not last the 10 years it takes you to get a stable income.
If that's your plan for your idea, then it's dead. Not going to work.
I'm scared to go all in and end up failing uni and failing to execute my idea. my parents are also hella unsupportive of any fastlane ideas so that adds to the problem.
So my questions are: what do you think? am I just making up excuses or is it a legit problem? should I just say F it and pursue my idea or at least do a bit of progress? Do I have the wrong mindset?
also I'm unsure if it's even possible for just one person to build something that works the same way as Uber
Your biggest problem though is your lack of ability and confidence to execute (likely do to a lack of ability).
It sounds like you don't know how to program, don't know how to tackle the problem, don't understand the steps necessary in order to undertake the problem at hand, don't know how many people it will take, ... don't understand pretty much everything from a business perspective.
If an investor asked you to write a 20 page business plan today, would you be able to do it? Or would it take you months before you even had a rough understanding of how to execute and get things done?
Here's my advice: If your idea is revolutionary, and you believe that YOU can execute, then start with a minimum viable product. Launch it before school starts. Then gather the support to seek angel investment or seed investment from an individual in the space that can serve as a mentor. The mentor/investor has to be someone successful that you aspire to be, not some doctor rich guy that you fooled into believing what could be a flawed idea. If you get validation from someone in the space, then push forward, otherwise don't.