Depends which version you read. Besides "young enough to play" doesn't nail down an age. I'm in my thirties and I still frolick, pick flowers, and play with friends. Plus we're talking about gods. Young to them could mean someone in their hundreds. Hades was a good guy as gods went but being a god of the dead doesn't bring in a lot of dates to someone's dating profile so he may have been a little desperate to get a girl's attention but he treated her with respected and was a loyal husband. And in the version of the story this fantastic piece of art portrays Persephone loved Hades back because he gave her freedom, authority, and love when her mother was a helicopter parents that refused to let her child go and spread her wings elsewhere