I'm 40, and I'm about to do an MSc in High Performance Computing at Edinburgh Uni. If I'm not too old, you definitely aren't. :-)
Seriously, whatever has happened to you so far in your life, it's in the past. It's *never* too late to do your best to make the most of today and of every day that follows - regardless of where you're starting.
If you're still having emotional difficulty, then please make sure you talk to someone about it. Find a friend, call a parent, see a counsellor - just don't try to bear it alone.