It's a shame the kids don't get much of a chance at being kids.
But, I'm sure they've been groomed for that since they were born.
I had read somewhere a few years ago that George had no idea he’d one day be King. I’m sure Kate and William did a decent job of trying to keep that under wraps for as long as they could. I’m also sure that they’re doing a decent job at trying to ensure all their kids are brought up as close to normal as they can be.
They’ll obviously be brought up knowing they’re different and being quite sheltered but they all attend regular school, have a chance to interact with kids their age, and seem to have parents who take a decent interest in them. Unlike someone like Charles who had pretty limited contact with his parents once his mother became Queen.
As for adolescence and early adulthood, there will obviously be a lot of pressure on him but he’ll still be second in line to the thrown until he’s in his late 20’s/early 30’s provided we have the current King in to his 90’s. While Harry is most known for being the wild one William did have moments where he was caught living it up like those his age did.