We all have "selfish" moments. Don't let them get under your skin or make you feel bad. We all have them. Those that say they don't are simply lying to make themselves look better.
That said, I encourage you to journal about these emotions. On paper and away from your immediate thought process, it's sometimes easier to make heads or tails of a certain thought or emotion. Yes, she is your daughter. No one is going to change that. And while no one can blame you from feeling insecure at times, you just need to make sure that those insecurities aren't interfering with your ability to parent your little girl.
Even parents who have not adopted have insecurities. It's our job, as the parents, to make sure that we're dealing with them in an appropriate manner and not letting them take over.
By coming here, you're showing that you do want to deal with it in a healthy manner.
You're going to be just fine. You're not alone. Promise.