Kia
First of all, You're not grown up. I mean sure, it's fun watching you take on responsibilities and such, but I don't think that turns you into a grownup. And it doesn't mean you can't have fun. You've got to, or what's the point?
Take a day and have fun. the world keeps turning even if you're not paying attention to every detail all the time. I learned that one the hard way.
What do you want to do? I'll blow off work with you.