She's all grown up!

Selena Gomez appeared on The Tonight Show Tuesday to promote her new single "Slow Down", and the singer dished to Jay Leno all about her recent birthday and turning the legal drinking age!

The talk show host asked what her first legal drink of choice was, and we have to say we were a bit shocked when she revealed it was whiskey! "I had a shot of Jack [Daniels]," she confessed before bursting into giggles when Leno asked if it was really just one.

So how did Justin Bieber's former lady love celebrate?

"I'll have a birthday party this weekend but I had a dinner with my friends, the party's going to be kind of a gypsy theme, I'm excited. We're gonna have skirts and tattoos and belly dancers. It'll be kind of the whole thing, it'll be fun!" she added.

We wonder if The Biebs got an invite?!