I don't think there's anything bad with gaming in your free time - at any age. In the end, why shouldn't one just enjoy whatever life's possibilities are? It's obviously important to keep all other areas of life under control, but what's bad about enjoying doing something - even if it's not productive - especially when you're young. This is quite philosphical, but I've found the idea of optimistic nihilism very helpful for having an overall more relaxed view on life https://you.com/search?q=optimistic+nihilism