I feel like it's okay to not like every part of your body. "You can feel beautiful despite your insecurities" is also a positive message. Liking every part of your body is a *big* ask. You can have insecurities, no matter how conventionally beautiful you are. Again, I think that's a positive message, because so many people think "the perfect body" is a destination, and really it's about figuring out what works for you, and accepting any sort of limitations you may have. If long sleeves make you feel more beautiful, more yourself, etc. by all means, embrace that. And honestly, her reason to want more coverage might not even have anything to do with body image. I'm a guy, and wear long pants year round. My legs look fine in shorts, but I prefer the way I look in long pants. It's just a personal preference. She could very well be in the same boat, but with her arms.