How do I know my baby is starting to roll over?

I finally got my baby to sleep amazingly in her pack n play. She is a little over 9 weeks old. However, when we woke up this morning she had literally kicked her way out of the swaddle and her arms were free, and she was all the way across the other side of the pack n play, sideways. It was crazy! Should I ditch the swaddle? I'm not really sure what signs to look for in her trying to roll over but she sure does kick a lot