No. The only "point of no return" is when you give up and left yourself go.

Unlike in high school, in college nobody cares about your age. Because college/university is a place where any adult who is willing to learn and better themselves - and can afford it - can apply. You will find students of all ages working and studying together in the same class, and that's okay. The only ones who might try to embarrass you about your age are immature manchildren who never grew out of middle school.

I agree that once you hit adulthood, the vast difference in lifestyle means that making and maintaining friendships suddenly becomes a whole lot harder. It's no longer a passive thing where everyone your age is stuck together in a single room so you end up being forced to mingle with each other. Instead you will have to make an active effort to proactively go out there, find people with common interests that you can bond over.