I want to become an actress in Boston, how do I start?

I am 15 years old and I really want to be an actress. I live in Boston, MA and my mom isn't willing to travel to another state or anything like that. I took an acting class as an elective in freshman year, now it's summer vacation and im going into renaissance acting for sophomore year next year (I hope that counts as experience) I need an agent but I don't know what is real and what is a scam. My mom also doesnt want to pay a lot of money for an acting class. just being in a commercial sounds good for starters. thanks and if anyone has anything to help that would be aweome