If the daughter thinks that a song is suddenly uncool or ruined just because her mum liked it when she was younger and wanted to share that with her, then pardon my French, but the daughter sounds like a bit of a cunt. I’m sure there are a lot of people here who have picked up some top tunes from their parents.
Of course we don’t see the full picture here, but I think it’s great that the mum sat down to play a tune that her daughter likes on the guitar.