When was the concrete placed?
What were the weather conditions?
How was it cured?
Did they apply a curing compound?
What did the contractor say?
What did the contractor tell you to expect?
Just looking at the picture, it looks green still and should even out as it weathers a little this spring. Hard to tell from the picture, and not seeing it in person…
I wouldn’t get too excited until late spring after it warms up for a while and weathers a bit.