There are so many ways to view it. The easiest way is to acknowledge that the past is just that, the past. I say If you're interested and she is interested, then go for it.
Some people have trouble with others pasts, people with these issues should probably avoid the relationship because it will weigh on them. I have a friend that is dating a guy who is constantly on her about her past because he is in his 30s and only been with 3 women, whereas she is 25 and been with 20-something guys. She REALLY likes him and would never cheat, but he has trouble accepting that she has been with so many guys and it bogs down their relationship.
In my case my GF has been with substantial amount more guys than I have been with women, many of whom are still friends in her circle. I could go off feeling like a schmuk and that they're laughing at me in their heads thinking that they got to sleep with her before me. But you know what? F*ck em, I'm happy and she is happy, so her past with them means nothing. When thinking like this, the decision is easy.
"All is fair in love and war." - Francis Edward Smedley