I think it's a fine decision,
My little brother is 19 years old,he left high school 3 years ago.because he was bored and he doesn't find anything interesting at school.
Recently i saw that he a lot interested in cars ( all men are ^_^)
So, i got informations and printed stuff for him about a school that helps you finish high school classes in private + they give diplomas for 'cars,mechanics,etc...'
I'm there to help him for sure,i truly hope he gets back to studies so he can find a good job that he'll like!
So, it's never too late!
Good luck 2 u :)