It didn't hurt my grades too badly. Of course, my grades were terrible in high school, lol.
I am leary on classes and stuff like that because that same sister ended up going to art school for college. She loved to draw and was great at it, so she decided she wanted a degree and make a career out of it. It made sense to get a degree in it. But when she went there, the instructors killed all the fun that she used to have out of it. Art school ruined her art. Now she rarely draws anything.
Also if you just want to draw something, just draw what you can. Ask others for constructive criticism. That helps a lot to get other's eyes on it to tell you thoughts.
Also if there is a technique that you are unsure about, there seems to be a youtube video on it somewhere. Can't draw hair, for example, go do a search and you will see pointers and advice about that and then implement it in your own art.