I mean, I didn't think it was that dramatic a change, but I think it would be hard for the League to not act differently having realized this adult guy they were hanging out with was actually a kid the entire time.
Black Canary's really the only one who kind of talked down to him as a kid in that scene, but I'd still say she's still trying to be respectful about it.
It's not even like it was an issue for the entire League. Red Tornado and Batman were fine with it.