Haha I feel like crossplay is much better received at cons than during Halloween or at school, so don't expect as many shocked reactions.
From personal experience, this is what I've learned to expect:
-If you pass well: "Ohmygod THAT'S A GIRL?!?" and people looking surprised when you talk (if you have a distinctly feminine voice)
-Requests for hugs
-Unexpected glomp attempts. Dodge them, or don't. It's totally up to you, but try to make sure no one gets hurt.
-LOTS of picture requests! Everybody likes a pretty boy and Jack Frost is bound to be a popular character.
-A lot of attention from fangirls.
-No guarantee of less attention from creepers, male or female.
Basically it's not too different from regular cosplay aside from some people's initial shock once they find out you're not the gender of the character you're cosplaying. I wouldn't worry too much about it
Bring friends and have fun!