Going back to school?

Okay im 18 turning 19 in sept on the 25th. I left school 2 yrs ago because of situations with my home life but I matured alot and many things have changed, for the better. I was never a.very good student, and didnt hav the best.grades, but I feel like im ready to go back. I was behind on credits quite a bit, and thats part of the reason I left. I wanted to know if I.could try and enroll back into highschool? I really want to get my diploma and prove to myself and others I can do it, I understand it will be alot of hard work but I am willing to do anything. Im curious if its also true that I CANT go back? People are telling me they coild decline me, if ao, what shoild I do? And how exactly do I go about going back? please help, tyvm