She looks to old to be singing the songs she does. Katy Perry gets away with it because she doesn't look her age.
Half the comments I saw on American Girl MV were "She looks so old to be dressing and acting like this" etc.
She doesn't have an appealing look to be singing songs like American Girl. She can try to have ADELE esque songs
But she can't have sexy, fun, quirky songs and expect to get popular at her age. It worked for Katy because she's attractive, has a unique voice, and has appeal. I don't know if Bonnie has those things (at least change your name. Bonnie Mckee will NEVER happen

)