3 month old and tummy time

my daughter is 3 months and I will be the first one to say that I have been a little lacking on doing tummy time do to the fact that we've been in the process of moving across country, she is able to push up with your head here and there and even is starting to look around on her own and is a

Able to hold herself up when sitting on our laps but she still is not lifting her head are rolling over during tummy time. should I be concerned by this?

Also how do I get her to do tummy time and enjoy it?