Can an adult child collect back child support from stepmother under Maryland child support laws

My father was a Baltimore County police officer before he died. He left everything to my stepmother. She also receives his pension since she chooses to not re-marry. I was 12 at the time. I am 30 now. Is there anything I can do to have her provide some sort of support for me? I realize that as an adult, I would no longer qualify for anything but, what about the years prevoius?