Tummy Time Help

My daughter is two months old today. She doesn’t love tummy time but some days are better than others. I think she holds her head up well. But I’m seeing other babies the same age that can already roll over and pull up onto their arms. Neither of which she can do. Should I be concerned? I try not to compare. I know all babies are different. I just want to make sure I’m doing the best that I can for her.