Yeah, I had a similar experience, not knowing masturbation was a thing girls could do, until years and years after I'd already been doing it. Not knowing that it was a normal and healthy behaviour, I figured something was wrong with me, and felt a lot of shame because of it.
Egen though I have consiously unpacked and rejected a lot of sexist ideas about womens' sexaulities being shameful, I sometimes think that the shame about masturbation I felt as a kid, is still affecting my ability to enjoy sex today.