Cracks in the concrete aren't usually a problem. As Dave says, bring it up with your PB and see what they say. If what they say doesn't make you happy post what they said with a pic of the cracks here and you should get some comments on what we think.
I talked with the PB on the phone. He said they are small surface cracks and will be filled and smoothed before the liner is installed. He said it was pretty common. The interesting thing is they poured it 3 weeks ago and usually a liner would be installed by now. I wonder how many new pool installs that this happens to, only you do not see it because a liner is put in soon after. I hope it is only on the surface and not a structural problem later down the road.