How to become an actress at this point of my life?

I am 17 years old, going to be in the 12th grade when the next school year starts up. I have had some experience, Ive done a school play and went to Barbizon School of Modeling and Acting for some experience. I have recently joined with L&M Modeling and Talent Agency in Baltimore, MD close to where I live in. It's not an exclusive you can only be with them agency, but I think it's a good start. They have nice auditions and jobs I could get. Plus classes I could take. I have taken my headshots and some pictures for my portfolio, but I wont be able to do any jobs with them until I receive them and that's probably in another month. But I'm still going to be graduating soon and probably moving away from here and the agency to college in a year. So I just want some suggestions on what to do in this years time and what steps I should I take after I graduate.