Exes Denise Richards and Charlie Sheen share daughters Sam, 16, and Lola Rose, 14

Denise Richards and Charlie Sheen‘s eldest daughter Sam is growing up.

On Monday, the Real Housewives of Beverly Hills star celebrated Sam’s 16th birthday with an Instagram montage of old and new photos of the teenager. (Richards, 49, and Sheen, 54, were married from 2002-2006 and also share daughter Lola Rose, 14).

“Happy Sweet 16 birthday to my beautiful Sami… 🌈,” Richards wrote. “My first born, ray of light, soulful, spiritual, wisdom beyond your years. I’m so honored & blessed to be your mom. It seems like yesterday that you were born.”

“I admire so much your individuality, strength, love for animals, compassion, confidence, passion, & from such an early age always standing up for what you felt was right,” she continued. “You are the best big sister, daughter, friend, and a great role model for your peers. I couldn’t be more proud of you and I respect you so much.”

While Richards said in the post that it “pains” her she can’t be with Sam due to her work schedule, she promised her daughter, “very soon I will be home to be there for you.”

“Have a beautiful birthday💕… I love you 🙏🏻❤️💋,” the reality star concluded her post.

In addition to Sam and Lola, Richards is mom to 8½ daughter Eloise, whom her current husband Aaron Phypers is adopting.

Denise Richards
Credit: Denise Richards/Instagram

Last summer, Richards opened up to PEOPLE’s Celeb Parents Get Real about the values she holds near and dear to her heart when it comes to raising her children.

“I think that my daughters will tell you that I’m a strict parent,” shared Richards, who previously revealed she had installed security cameras outside her home to prevent Sam from going out to meet with boys without her permission.

“I definitely have rules and boundaries and there’s consequences,” Richards said, adding that she doesn’t let her daughters “do whatever they want.”

Denise Richards
Credit: Denise Richards/Instagram

While the Bravo star admitted that one of her daughters can be “extremely headstrong,” she said she recognizes the positive values in that character trait as well.

“My father said, ‘It might be challenging right now, but when she’s an adult, you are going to be so grateful because she is going to be one strong woman,’ ” she explained.

“And that’s when I was like, ‘Okay, that’s my daughter,’ because I’m pretty sure I was probably very similar with my parents,” Richards added.