Best friend to girl friend. girls and guys answer please.?

ok. so im not a shy guy but i am afraid of taking signs to mean the wrong thing. im not very good with body language, but i flirt with every girl i talk to. but i have a crush on this girl and i've had it for about a year and she has been my best friend for 2 years. she has started acting weird around me after breaking up with her bf (and while dating her bf toward the end of the relationship) and i dont know to take it as a crush on me too or to take it as she was shy but not anymore or what. if i tell her i like her it could mess up the friendship and i dont want to do that. i hang out with her at her house and stuff but we are NOT friends with benefits. so what should i do? i need ideas to tell her i like her without coming out and telling her until i know she likes me back. tomorrow im going sledding with her and some of her friends if that helps at all.