How can i tell if shes interested?

[Jack]

Basically ive started hanging round with a group of new people who are same friends as my sisters and recently we went to leeds festival but my sister never ended up going and i started to like a girl who is good friends with my sister we talked a little through out the week but nothing special when we got back i started to talk to her on facebook we had a some good convos i really enjoy talking to her when we have stuff to talk about. About a week after the festival everyone went to this party and she was there we was talking alot and flirting we was both rather drunk and i could rather tell she was a little interested as another girl there was constantly trying to pull me away for some "alone time" and everytime she did i could tell she was jealous and she even pullled me away from her at one point towards the end of the night she was with me alot and we even shared a taxi back. after the party i left it a day before talking to her again as i didnt want to seem to keen but the thing is she never talks to me first on facebook im always starting up the convos and some times it just seems she cant be botherd and last night we was out again at a little gathering at a bar i really wanted to talk to her but she never gave any interest towards me and when i started up a convo it just seemed blahhhhh im not sure if she likes me or she might just be a bit shy or is it that she dosnt want to annoy my sister? i really like this girl but ive never really been in this situation before and i have no idea what to do i even felt like telling my sister last night but i decided thats a bad idea.

[Wascally Wabbit]

ask her out-