5 mo old not picking head up or rolling over

I’m worried. My son will be 5 months this month and doesn’t really like tummy time. He picks his head up just a little bit only for like 5 seconds if that. He also is not sitting up but he’s trying. He’s not rolling over either. He tries to but just can’t. I’m worried cause it seems like other parents are succeeding in helping their children sit up and learn to roll at early ages but I’m failing at it. Is it okay that he just hasn’t learned any of these things yet or am I doing something wrong or is something wrong with him ? I sit and use a toy to try to get him to roll over and I sit him in a bumbo seat to help him sit up. I’m just worried. Is any of this normal