What? A sweet sixteen is a coming of age party celebrating a girl's sixteenth birthday in North America; primarily in the United States and Canada. When? September 30, 2011. Where? Aliso Viejo Conference Center. Why? I think every girl wants to have a Sweet Sixteen. Review: It was INCREDIBLE! So many people and so much fun! 756 Photo Booth Pictures! I was so happy because I actually got to celebrate my birthday on my real birth date!