Is she actually interested here? Or just playing around with me?

wow it sounds like this girl has split personalities.... hehe... or it sounds like she just likes to mess with you. if she treats you differently when her friends are around, then she's not worth your time. you dont want an immature girl. the fact that she "flirts" with you, doesn't mean she likes you, some girls just have flirty personalities. and a lot of the times its commonly mistaken that she's a you know... but that doesn't mean she is. if you're into this girl then ask her to lunch or something. the worst thing she can do is turn you down. there are other fish in the sea. but there is only one way to really find out if she likes you... now the question that you need to ask yourself is, are you a man, or are you a mouse?