I was in a near exact situation when I was going to college:

1. I was accepted into MIT
2. I was also accepted into my hometown college (Texas Tech University) with a near-full ride scholarship.

My parents could help with the rest of the TTU tuition, but wouldn't be able to even cover ONE semester of MIT. MIT is VERY expensive and the only option would've been to take out tons of student loans.

As others have suggested, you need to be scrambling for financial aid. I wish I'd looked harder, but to be honest, it's going to be tough. Even the most wealthy cannot really afford MIT. And to get an academic scholarship at MIT?! That's going to be very very tough. Then again, these are all the things I told myself. So maybe try what I didn't.

I ended up attending TTU. To make the most of it, I did a dual-degree program (Electrical Engineer & Computer Science dual-degree 5 year program). It was intense, but in the end, I have two B.S. on my wall. I put my everything into college and kept my GPA up. I consistently held myself to the standard that MIT would've expected. I ended up not going to grad school because it would've also required student loans. I also got a job out of college. So making money made way more sense than pilling on debt.

So by going to the small college, I ended up coming out with a paltry $10k in student loans. I paid that off fairly quickly. Thereafter, once I had my first job under my belt, what college I went to literally didn't matter one bit. I now work at FAANG alongside people from other no-name colleges as well as the Big Names. No one cares after you're 25-30 and have a couple of years under your belt. I could go work for a startup now, but literally only because I have no student loans (hell, I even paid off my wife's grad school loans).

In hindsight, it actually worked out super great that I didn't go into MIT. Not having student loans meant that I could focus on getting ahead in wealth and in life. Again, all said, focus on giving yourself as many opportunities and options, that's the primary advantage of your age.

(On a personal note, I made my best friends and met my wife at TTU, so even with a time machine I wouldn't risk it).

I know people talk a lot about the network effect, but TTU also had a network, and any college will as well. Maybe not as top-tier as MIT (by definition) but it was also more friendly. When I visited MIT campus-preview weekend, it was greatly divided by houses, which were divided by a class/wealth hierarchy. The "good" houses were even more expensive (don't forget to account for room and board!), so everything is continuously gated by money. At TTU, all the dorms were just dorms. There was some greek life but anyone could join the professional orgs and that's what really mattered.

But from a purely objective financial perspective, not going to MIT didn't hold me back one bit as I still hit all the goals I set out anyway. And now I make $300k+ a year and it's all mine (debt-free except for a mortgage).

EDIT: Also, Congratulations! Getting accepted is great and you should take the moment to be proud. It's also a strong indication that you're going to do very well either way. Z is low-risk, moderate-reward. MIT is higher-risk but also upmost-reward.