"I have a birthday month," Cyrus, whose actual birthday is Nov. 23, told Access Hollywood. "I do the whole month of November. Thanksgiving, cake, [it's] all about me on Thanksgiving!"
Fresh from her performance at the American Music Awards Sunday, Cyrus donned a black leather halter top with feather straps and black leather pants by WTB and headed over to the club with her mom, Tish.
Guests at the party included Demi Moore, her husband Ashton Kutcher and daughter Rumer Willis, Kelly Osbourne, Kyle Massey, Mark Salling and Chord Overstreet. (Cyrus's dad, Billy Ray, who is divorcing his wife Tish, was working in Nashville).
Later in the night, the birthday girl was spotted kissing fellow teen star Avan Jogia, 18, who appears on Nickelodeon's Victorious. But a source close to Cyrus tells PEOPLE, "They're just hanging out. She's still single."
Another source tells PEOPLE that Cyrus and Avan "have just hung out together a few times and are getting to know each other – that's really it right now."
"She had such a good time [at her party]," says a guest. "She was so happy and having so much fun just dancing nonstop, surrounded by all of her friends. It was the party she was hoping for."
Guests enjoyed music by DJ Cobra, a giant red velvet cake with cream cheese frosting, along with Key lime pies, chocolate mousse and raspberry shot glass, along with a cake and dessert table, all by Sweet & Saucy Shop.
Reporting by MARISA LAUDADIO