I think each one is beautiful and good in its own right. Being a child means less responsibility and more freedom in the sense that you don't think of the consequences of everything. On the other hand, being an adult makes you consider things more deeply. But even though adulthood means bearing more responsibility, it also makes you more independent and thoughtful; you get to see things and understand them in a different way, and maybe a more beautiful way, than you used to as a child.