Think its too soon to be rolling it, grass is not strong enough yet, only down 4 weeks, rain is coming soon, don't panic, I would say re=seed the bald bits and wait till later for the rolling, let the grass get established first. I'm actually waiting to roll mine too, but the ground is still a bit too wet at the moment, believe it or not. Tractor mower is leaving tracks in it in parts. Waiting for it to dry out a bit, then I'll tackle the rolling. Ours was sown last September, unfortunately a flock of sheep in hight heels got in earlier this year. Still filling in the holes !
Secman