It's never to late to learn. I congratulate you on your persistence and perseverance to finish.
I was a terrible HS student - 6 year plan, 4 years, 2 summer schools. I wasn't allowed to walk in the ceremony and spent my senior summer in summer school.
HS in the 70's for me was exactly like the movie 'Dazed and Confused' - hence all the extra class time
10 years after I graduated HS I finally graduated College. This time it was because I was married, working full time trying to fit classes in.
My Hats off to you