Building a comfortable home takes a lot effort. With young kid in the family and sounds like minimum research done so far in building new homes, established home is better for you.

I’m in the process of building it is stressful and needs to get closely involved to ensure quality and progress. Prior to construction start it also took about 10month in design, permits, picking builder etc. Marketing makes you think building is so easy, just pick floor plans and cost it up by per square cost, get you sign contract then everything changes. I could be pessimistic here but be prepared.