All of the new homes use a polymer grout, and do not need to be sealed. You can easily test this yourself - put a drop of water on your grout, if it sinks in quickly, you should seal. If it beads up, you're fine. We had someone come in to clean our tile and were going to get it sealed. They showed us that it didn't need to be sealed, and explained why. They were more than willing to seal it anyway, or course!
Our home was built in 2017, and grout used was Mapei Ultracolor Plus. If you look it up, it is polymer, and designed to repel liquids.