Which is more playful a boy or a girl bearded dragon?

Well it does not matter either way, male beardies can be more aggressive than girls, but not like bite and scratch. Most beardies are pretty mellow, and I have owned two over a period of 10 years. Females tend to go through a period when there are eggs in their body (fertilized or not) when they like to be alone, although this period is not long. And as for males, in mating season they get hyper. I would suggest you get one either way, it does not matter. Just ask the breeder or pet store owner if the bearded dragon you have selected is kid friendly or aggressive. As they get older they become less playful and slow down, around 5 years old or so. But they are great pets to have and a great recommendation for a first lizard. They usually live to be around 8 years old if they are in good health.

Hope this helped :)