I just started a relationship with this girl about a week and half.she just Graduated....

Before she met me she had a 5 years relationship with a guy and they lived together, then they broke up, she says it was perfect they just had a financial dispute. After that she met another guy who she was with 6 months who treated her badly and they broke up about 3 months ago.
Now we are together, she accepted to be me with me, she says she likes me, calls me a lot, we had sex many times. Thing is, I don't mind her talking about past boyfriends, but she brings it often, even if I'm talking with someone else.
Is she just hurt? Or does she has some lasting feelings for any of them? At first I didn't mind, but it's starting to bother me a bit. I'm starting to feel secondary to her or even worst, a rebound.
I really enjoy her company and her personality, she's very sweet and I like her.

What you Guys think about this? Could it be a problem or it's just temporary? How can I as a teenager do better in a relationship if she says someone before was perfect? Leaves me somewhat confused, I try not to intice her to talk about this and sometimes I swap the topic of the conversation.
I know our relationship is recent, but I'm just trying to get another opinion from you guys, who have been through the same or similar. Thank you. waiting for reply