Nah, my mom didn’t know much. And she was Baltimoron.
Of course, she (and I) is not a typical “fan”. She was not into celebrity nonsense like concerts, and fan magazines, or screaming and fainting over them.
Probably more like me - I listen to music, and don’t much care about the details, and just happen to notice when an act is consistently good that we like them. Couldn’t name members of any given group, but I know what their hits are. Just don’t care to know everything about them.
With the Jerry Lee scandal, it wasn’t so much about fandom as about DJs “cancelling” him, and there had to be a reason that was talked about on the school bus, and our parents disapproving of continuing to play his 45 records in the basement!