I think she was hoping he'd tell her he liked her hair, since he clearly liked it when Maho-chan did it for her at school. But I'm sure she'd have been thrilled with him saying that, too.
I like how the artist even showed that Mei's painted her fingernails, and they're blue to match her dress. Kaede won't notice that, but it's clear she wanted to be as cute as possible while spending time with him.