Tummy time

My baby boy is 8 weeks now and I keep seeing videos of babies around his age already lifting their upper bodies when on their stomachs. I’ll admit, I haven’t been very good at remembering tummy time so I understand why my LO isn’t doing it as often. Was just wondering how long it took for your guys’ LOs to start lifting there heads and upper bodies? He has done it several times, he just doesn’t stay up for long.