Heather Rae El Moussa Celebrates 'Beautiful Bonus Daughter' Taylor on Her 14th Birthday: 'Love You So Much'

Heather Rae El Moussa is celebrating her stepdaughter Taylor 's special day!

On Sunday, Sept. 22, the Selling Sunset alum, 37, marked Taylor's 14th birthday by penning a sweet tribute to the teen — who is the daughter of her husband Tarek El Moussa and his ex-wife Christina Hall — on Instagram .

"Tay, I can't believe you are 14 today! It went too fast ," Heather began her post. "You have grown up to be such a beautiful, driven, sophisticated young lady. I love watching you with Tristan and I am so lucky that I get to have you as my beautiful bonus daughter, I've loved every moment with you."

"I love you so much, happy birthday sweet girl. ," she concluded the tribute.

The words accompanied a carousel of cute images of Heather hugging Taylor throughout the years, — including when Heather was pregnant with her and Tarek's son Tristan , now 19 months — while a few of the photos also featured Tarek, 43, and his and Hall's son Brayden , 9.

Sharing her love for Heather's post, Hall, 41, wrote in the comments section "."

Meanwhile, on her own account, the HGTV star wished a Happy Birthday to her "first born" alongside a mother-daughter selfie.

"How can she be 14?! If you watched 'Flip or Flop' since the beginning you watched me carry Taylor on my hip through all of season 1. I didn't have a sitter and didn't want to be apart from her- so she was along for the ride. Time has flown by way too quickly," she wrote, before sharing that her daughter "changed my life in all the best ways."

"She challenges me, holds me accountable and makes me want to be a better person," she continued. "She's wise, strong w-lled, talented, beautiful and so fun to be around. She's literally my favorite person and I'm so incredibly blessed to be her mama. ."

Her post comes after she treated her daughter to an early birthday dinner on Friday, Sept 20. Ensuring Taylor celebrated in style, Hall took Taylor for a glamorous birthday night out at the Ocean 48 restaurant in Newport Beach, Calif.

Heather and Tarek offered a glimpse of Taylor's celebrations on their Instagram Stories on Sept 22, with the couple filming the birthday dinner they threw for the teenager. One video showed loved ones around a table decorated with pink and white roses, while another showed Taylor and a friend being presented with a birthday cake as the table sang "Happy Birthday" to them and they below out their candles.

Tarek also posted a picture of himself and Taylor smiling at one another with balloons in the background and the caption, "Can't believe she's already 14!"

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On his grid, the proud dad penned his own sweet tribute to his daughter, writing, "My little girl is 14. It went by so fast I could almost cry, but I've cherished every moment. She's a strong, talented, beautiful young lady, and I couldn't be more proud."