Caitlyn Jenner turns 66 Wednesday, and while this isn't a milestone age, it's a huge deal for the reality star, as it is her first birthday as Caitlyn.

She has had a huge year between her Diane Sawyer interview, her transition, her Vanity Fair cover, her hit reality series "I Am Cait" and her legal name and gender change, so celebrations were definitely in order.

Caitlyn, her daughter Kylie Jenner, her step-daughters Kim and Kourtney Kardashian, and Kourtney's daughter Penelope decided to get the celebrations started a little early this year by going to a birthday lunch on Tuesday, according to Us Weekly. The girls met for lunch at The Villa Restaurant in Woodland Hills while camera crews filmed the outing for either "Keeping Up With The Kardashians" or "I Am Cait."

Kylie took to Instagram to wish her father a happy early birthday with a sweet message. "Early birthday lunch with @caitlynjenner," she captioned the selfie. "Happy birthday dad what an amazing year for you." She also posted a few photos of the two to her website and app writing, "Happy birthday Dad! I love you so much and am so proud of you! I hope this next year is filled with love and happiness! Love, your baby forever."

Caitlyn looked chic and casual in black leather pants and a black printed top while Kim rocked a blush colored dress with a matching long coat, which has been her signature maternity style lately. Kourtney wore knee-high black boots and a green jacket while Kylie stunned in a black Alexander Wang mini dress.  Khloé Kardashian, who has been spending time with her estranged husband Lamar Odom, was not able to attend the lunch and Caitlyn's daughter Kendall was also absent from the event.

Sixty six is going to be another big year for the reality star, as "I Am Cait" was recently picked up for a second season, and she has become a huge inspiration and mentor for the entire transgender and LGBT community. She also recently announced that she will be embarking on a speaking tour called "Up Close and Personal" in February 2016.