Is my baby being good? :\?

okay, so let me first give a bit of context, and I'll keep this as brief as possible. My girlfriend who I love to death had a financial issue about 6 months ago.. she was forced away from the college we both had been going to, to having to go elsewhere to study. We have been in a shakey long distance relationship for about 6 months now, and she comes home to see me in about 1 and 1/2 weeks. I have been checking her facebook in anticipation of her return and I had noticed some pictures. She is in hawaii right now, which is where she is from, and because she is not working she has a lot of free time on her hands. I see pictures of her partying, playing beerpong with her old friends from hawaii, etc etc. MY question is, If she HAS cheated on previous boyfriends (though her past boyfriends were s) is there a good posibility that she is cheating on me? I love her to death and she loves me (we had been together for a year before she moved.) Should I be worried?