i would say start with some voice lessons. if you college has a music school, there are probably some grad students who would LOVE to have a new student. if there aren't, try looking around the area to see if you can find any voice teachers.
also, DEFINITELY get involved with something!! even if it's a tiny community production, it'll give you an idea of what being on stage is like, even on a small scale.
if there's an acting class at your school, try to get into it!! it'll help build your skills and give you a better idea of what you want to do.
best of luck!
"grace, you're stuffed in a box getting rid of ass plaque. let's face it, this evening is a bust."