Student loans suck, but I think it is very wise for OP to seek out the best education he (or she) can.
I think it is premature for OP to seriously plan for the future, except to know that time spent in the library that first year will really pay off. There are a couple of people who can figure out their future when they're 17, but when I was in high school I certainly wasn't one of them.
One of the great things about university, especially at the best places, is you'll meet ambitious people who have goals you'd never contemplate before.
And Ivies are not just about name recognition. I know people who went to Harvard and Princeton. They learned soooo much. Perhaps as much or more from their peers than from their classes, but it's still worth it.
For most people, going to Harvard would be cheaper than attending a state university.
Right now, the unemployment plus underemployment rate for recent college graduates is 53%. Quite a bit higher than the national unemployment rate. $100-200k in student loans (which will cost closer to $300-400k to pay off with interest) doesn't make it easy to get by even if you landed a great job. A low-paying, risky startup job might not even be a realistic option once you're saddled with debt.
This is the time to think about things like that -- what you can afford, how you'll repay it, what kind of job you want when you get out, where you want to work, whether the name recognition of an ivy league school matters to those companies (and whether that's worth as much money as a small house versus going somewhere cheaper), etc.