I'm 37 and still terrified to drive. You are not alone -- actually it's great that you at least have your license, so that if you get into a situation where you have to drive, you can even if it's scary.
I don't really know how to get over this :/ I've been pestered by people all my life about it.
I hope you'll be able to get used to driving to school, maybe it will get easier the more you do it. At least it will be one familiar route.