I have a super jealous streak, and I don't ever hesitate to show it. Particularely at parties when I leave the boyfriend for a few minutes and see some random girl approach him. It's fun
I know in my heart of hearts that nothing bad will ever happen, but it's a good thing to want to be a little possesive of your man. It shows you care
Now, about your situation. I think that if she's being honest with you about everything, you have nothing to worry about.
Just keep in mind that you need to treat her special for choosing you. If for some reason she doesn't feel that way for a long time she will know that others find her attractive and maybe move on.