Discharge

I know that discharge is the way the vagina self cleans itself. The thing is I don’t have any. Like at all there is never anything in my underwear. (I’m 16) and I used to get it around 5th grade but I haven’t since. Is this normal? Is my vagina still cleaning itself? I haven’t seen my gyno in about two years and I never thought to bring it up. Should I be concerned? I could ask my mother but I’d prefer not to. Any suggestions?