I WANT GO TO SCHOOL

I am 19 year old. I have been studying for three years in Georgia. this year is my last year in high school，but my family need to move other state. This state is Alabama. I hope i can get high school in AL. but they teacher say i am too old for the high school. Is 19 too old be a senior（so many student in that school is old 18）？they tell me go back to GA to finish my high school. All my family are move how can i go back here? I just want to finish my high school why is so hard. I hope I have the right to education, here the school will start on August 19, and I can only look at the windows in the house？