I’d recommend forgetting your ballpark estimates, they’re pretty far away from what’s possible, they’re much closer to worst case than best. It’s probably not going to take 12 years. I’d also recommend going to college only if you want to, not purely for money, because it’ll help you get into work you aspire toward, or because you’re curious and love to learn. Talk to the school you’re interested in; if your income is low they offer all kinds of assistance, not just loans.

FWIW, I took student loans to pay my 4 year degree. I too thought it was going to take forever to pay off. Turns out it didn’t, I had them paid off in less than 4 years, after deferring them for a couple of years to do a masters.

I do have a wish list for our country to make education better and more accessible and less scary to people like you who want to go but worry about the finances. In the mean time, I hope you find a way.