Am I being paranoid?

Hey, i'm new to the forum.. hoping you guys can shed some insight on my situation.

I'm seeing a girl long-distance, we met about 6 months ago through a mutual friend.. we see each other for about a week every 5 or 6 weeks. She's a 1 hour flight from me and we both make efforts to see each other. She's 21, i'm 25. Everything is going well and she's been talking about moving down here next yr. However i've started really liking her, more than i have anyone in ages but with that has come a feeling of paranoia and occasional jealousy whenever she goes out and parties with her friends. Basically it stems from a night not long after we first got together, she sent me txts at 2am one night trying to get a rise outta me which totally worked.. something along the lines of 'hey you i'm really turned on and you're not here..' then 'I'm with kyle and i'm turned on and you're not texting me back' 'You better txt me back, i'm seriously turned on i'm with kyle' etc etc. He's a close friend of hers from their circle and from years back whom she had a couple of brief encounters with before i came along, and i know there's chemistry between them. That's way back though and she apologized profusely and has never done anything like that since.

But ever since she did it i get intensely jealous whenever she mentions him. She also tells me about guys who flirt with her at bars or other guy friends whom she's had moments with before me but whom she also still hangs out with a lot. She's only slept with 3 people before me but i cant help but feel jealous and constantly wonder all the time since i'm not there. She's going to an end of school party this weekend and is staying at a guys place who she has got together with before (but not slept with) along with about 10 of her friends. Am i justifiably jealous and paranoid? Or am I being ridiculous? I've been cheated on once in the past, she knows this and always says she's not like that and would never do it, though alcohol.. other guys and history with them makes me doubt.

I just don't want my feelings of jealousy to ruin things between us if they're not justified, she has no idea i feel like this. I don't like feeling insecure about the whole thing. Any advice appreciated, especially from you girls

Also on a lighter note, i like her so much more than i have anyone.. i dont think i've ever experienced 'love' could this be it? Should i tell her?

Thanks, sorry about the length!