There are pros and cons for either demographic: whilst being older may be ideal since not only you bypass age restrictions, you also have the capability on purchasing it with your own money without having to ask parents for that given that you have employment and recurring income. Gaming as a kid gives more time without having to dwell much on responsibilities that adults have to worry about but at the same time are held by school.
This so much.
Gen 3 Pokémon games which I mainly played as a preteen were basically my second home, I knew almost everything there was to know about them.
Games I played later in life, including later Pokémon games, I mostly forgot the details after playing.