I'm not sure how much I could contribute (still in University), but speaking from my own experiences with semi-realistic goals and hobbies, I'd encourage you to start planning it out as a small business, just to see how feasable it is.

So you'd need a database for the drivers, a way to test and then add new drivers (since it's starting out, you could do it by hand), a database for the users, a user-side and driver-side app (this would be the expensive part. If you're ever bored, try learning how to make an app (I say as a Computer nerd), but honestly this would be the toughest part of the startup). Etc etc. At least putting it on paper might help organize it in your mind and assess if/when it's viable.

Back to the general questions.

If it helps, you in 3 years will definitely have a different opinion on what you should've done. That's inevitable, and that's okay. What really matters is figuring out clear goals now, so that finding what you should work on becomes much easier.

Live a life full of adventure/travel (if you want to) and worry about being a parent when you get there. Working backwards, being a healthy father would originate from a loving relationship, and the key to that is living a satisfying and fulfilling internal life. Love yourself, and respect/pay attention to others, and that bit will work itself out, I believe.