Yeah, the lingerie line switch was mind boggling. I assume they didn't want a high school character singing about wearing lingerie for her non-high school boyfriend? Either way it was a stupid move. They clearly had issues with Marty since that scene between her and Mario Lopez's character played incredibly awkward...it didn't help that Lopez was so godawful and Keke Palmer was left to do all the heavy lifting.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"