@Leucrotta If the things you use in your art weren't things taught in your class, then yes you count as a self taught artist. And even if they were taught in your class, you count as a self taught artist, because you taught yourself stuff anyway.
And no, it doesn't matter anyway. You are an artist. Period. You are a creator and net reducer of entropy. And you are valid and good and valued.
@Leucrotta It really isn't. And I say that as card carrying member of the official self flagellation club. But I know how hard it is to quit and I see that struggle. You're not alone.