“Kick some butt out there!” She smiled sweetly and turned to return to her seat in the crowd.
The 'S' in 'She' needs to be capitalized because 'smiled' doesn't have anything to do with the quote. If it were 'she said' or 'she shouted,' then yes, the 's' would be lowercase. But since you can't smile words, "She smiled..." is a brand new sentence. I suppose I should separate it from the quote, but just sayin.
Anyways, thanks for reading all of you.