How far should I take my costume?

I am wanting to cross dress for Halloween this year, however my girl is being apprehensive about it. I am doing what she would like to (as a fortune teller) one of the nights however I am going out either with or without her one night in a costume of my choice (cross dressing). I want to take it as far as possible, but as she is the one helping me and she doesnt like the idea, how far should I take it? Please help me out! I am 25 male, and outgoing! Thanks!