It's not going to hurt her. All my life, my mother has worn long pants during the summer. Some of dd's friends wear long jeans during summer. And we live in the deep south where it's very hot. Your dd is just going to get hot, and that's her own problem. You could show her some cute capris or bermudas that are longer than shorts. Actually, my dd won't wear girls' shorts. She says they're too short, and dd has a nice pair of slim legs that would look great in shorts. She always wears capris or boys' athletic shorts (which go to the knee). It's my dd's choice. I've never tried to force her to wear something different.
Good to know I'm not the only one having deja vu. lol
I thought it looked familiar as well.