tummy time

So my LO refuses to do tummy time! I've even tried laying her on me, waving toys and talking to her, I've tried rubbing her back while laying down, turning on the the Tv for her, reading her books, everything I can think of, but she just won't do it! 😫 she's little over 3 months now and every time I do try to encourage her she cries and cries. I'll turn her back over on her back and she's perfectly fine, but then she tries to sit up and gets frustrated when she can't. She still can't hold her head up so when I do sit her up I just put her in front of me with her back resting up against me. It seems like she just wants to skip rolling over and wants to go straight to sitting up instead. Do babies have to do tummy time in order for them to be able to hold their head up around the time their supposed too?