Tummy time help please

Kerensa

So when I do tummy time with my little one she just lays there eating her hands, falls asleep or just cry’s. I try to help her but she won’t do it. People keep telling me she should be supporting her head an body and rolling over by now. Witch makes me worried. She will be 3 months on July 5th. Should I be concerned and is there anything else I should be doing to help her??