Tummy time is a waste of time! It is designed for people whose babies lie in cribs or car seats all day. If you are carrying your baby, she is developing core strength anyways.
She seems right on track to me. My first son HATED tummy time, so we didn't do it, but he sat, rolled, crawled and walked a bit later than some, but was fine and the pediatrician could have cared less. But we joked that he was a blob. Just happy to lay around and watch the world go by. He's an active, bright, outgoing 2 1/2 year old. Just didn't need to get moving too early.
Her needs are being met right now and she doesn't seem to have the need to be enticed. She will crawl when ready.
And yes, ignore those who want her tested...she is just doin' her thing.
My second one does tummy time for 30 seconds, then flips himself over to his back, so there's no sense in doing it with him either, or I'd be flipping him back and forth the whole time.
These are all just guidelines. Enjoy the late crawling....she will wear you out when she starts! :)