Rolling over

So at first my baby hated tummy time, she would only last a few seconds before she started screaming. I just did as much as I could a day and eventually she learned to like it. I was kinda of worried at first but one day I laid her down and she didn’t cry and she raised her head so far up I was super surprised and she’s been good ever since. Now she seems to like it. She would roll over here and there randomly like once out of every 5 times she would do tummy time, so I didn’t really count it as her accomplishing it. Well the rolling become more and more often. She was rolling over almost every time I put her in her belly there for a while but here lately it’s like she has forgotten how to roll. She hasn’t rolled over in a while, but I know she can because she was getting pretty consistent with it. Is this normal? Has anyone else’s baby done this?