Hello
First of all congradulations for considering going back to school. Secound don't let the public speaking issue stop you. It seems to me that this is just another lesson in life to overcome. I come from New Zealand but I assume western countries run the same support for students.
SuggestionS:
most collages have a counsellor to talk to, go visit them, they could help you overcome your fear.
Join or start a adults returning to school support group.
Join the student help centre, they could coach you through your fears.
So get support, find out ways to overcome it, or at least manage it so it doesn't stop you doing something you want to do! If the above isn't enough for you to get over it, maybe going to counselling for a while may help, it may be connected to some deep issue. I hope I haven't been to pushy, that isn't my intent, I write from my own experience as I too am shy. So goodluck.
michelle