I suggest you go to the local Bar association and ask if they have a volunteer lawyer section that can help you.
I don't practice in your state, but I suspect that since you were 15 at the time, your record should be automatically sealed or expunged upon reaching majority.
many attorneys do pro bono work, but it may take quite a few phone calls to find the person willing to take your case. You may want to approach an attorney that you are not looking for a totally free ride, but need some help with payment plan. sometimes, attorneys will lower their fees for someone in genuine need, but are reluctant to do so if the person is looking for a freebie right off the bat.