How should I deal with this girl?

It all started about half a year ago, when I really started to like a girl I knew. I have plenty of friends (mostly guys) and am graduating next year. The thing is that I have been a friend for this girl and she is 2 years younger than me. However, recently she has been acting really flirty and I really think she enjoys my company.

Whenever I am alone (like right now) I get thoughts that she doesn't like me and that she is not interested, but when I am with her I know she is enjoying herself. She laughs at things I say, makes eye contact, and engages in conversation.

The thing is, I have no clue if she has a boyfriend, or if she acts this flirty with every guy she knows. She lives really close by so we hang out often.

Recently I also started texting her and it is driving me crazy. Sometimes she has a long conversation with me which again, is flirty. Sometimes I say something and she doesn't even respond. Confusing as hell. She has been away on summer break and when she finally came home I hung out with her 2 days in a row and I think she had a great time. Today when I texted her first (always the case) she asked to hang out even when I did not ask to hang out. So I definitely think she enjoys my company.

The only thing that discourages me a lot is that some guy keeps commenting on her stuff on facebook and is acting exactly as a boyfriend would..."i really missed you <3", "love u too", and other stuff like that...when she got braces he even said "awww, no more kissing"...to which she did not respond. So my guess is she is going out with him??? no clue.

she acts pretty flirty around me. So what should I do? Wait to see some change? or make a move? I obviously flirt back but nothing too obvious.

Also, the same guy that is her "boyfriend" texted her a few months ago while I was with her and after I asked her who he is she said "some annoying guy"....who she now is going out with??? So confused...

They might not be in a relationship, in which case she's available to you.
Have you asked if she has a bf?

I'd assume she has a boyfriend but shes enjoying the flirts with you. She hasn't mentioned him to you, probably knowing if you knew she had a fella you wouldn't make so much effort with her to make her laugh, chase her etc.

Shes enjoying the best of both worlds. But that might not be the case, she might infact be single or in a relationship with a guy that doesn't make her feel that great to scream it form the rooftops.

Just ask her

I should probably ask her. However, I dont know if I should ask her directly or in a more subtle way. Also, wouldn't asking her that question automatically tell her I am interested? Is that a good move? Thanks.

I'd ask if she has a bf directly without mentioning what you've seen in fb. And yes, I think it's a good move to let her know you're interested. Assuming that you are.

Ask her in a subtle way, I would. Maybe something along the lines of, 'your bf must be a cool guy in that he doesn't mind us hanging out as much as we do'. She will surely know why you are saying it but nothing wrong with it in my opinion.

Say outright "Dyou know what, I cant believe how long i've known you for now and i've never even asked if you've got a boyfriend?!"

Ask her if she has a bf directly. That way she knows for sure, that you like her for more than a friend. She can chose to act on that information, or not.