This year, Santa gave my son (age 4) the EG Gundam, GQuuuuuuX (HG). We divided the work: he removed it from the runners, I lightly finished the gates and inked it, and then he assembled it. He seemed to have enjoyed his first plastic model, and finished it that same day.
As he made it himself, he seemed to really like it.
While he was playing with it, he wanted to watch the first Gundam, so we watched the first episode on Amazon Prime. It was a strange sight to see someone born in the Reiwa era captivated by the first one.

My First Plastic Model | 応花's Gunpla works