It's just having the maturity to realize that you don't have to stop having fun just because you're getting older
It's also important to have the maturity to realize that there is a time and place for embracing your inner child
I have a tattoo of a sword buried in molten rock on my bicep. It was kind of inspired by the bonfire from Dark Souls. I don't tend to go around showing it off at work events or whatever.
I absolutely do not regret it even though it is admittedly kind of a childish tattoo. I think it's cool. I show it off to people that I think will also think it's cool