The Fifth Harmony ladies are all of legal ages now!

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Dinah Jane Hansen, the youngest 5H member celebrated her 18th birthday Monday!

The 5H singer was quick to post some photos of herself to Instagram as an 18-year-old, but she wasn't the only one celebrating her birthday.

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Ally Brooke Hernandez, Normani Kordei Hamilton and Camila Cabello also joined in on the birthday celebration via Instagram.

Hernandez, the oldest 5H member, shared a set of three photos of her with Hansen, mostly showing off their goofy friendship as well as a sweet message. "The last one to turn 18!" Hernandez gushed, before adding, "All my girls are grown ups!"

She even pointed out how much Hansen has transformed, "from the timid, barely-speaking-a-word Dinah to the FEROCIOUS, vivacious Dinah," which she deemed is "a blessing."

Hamilton went the route of sharing a video of Hansen dancing while wearing a jersey that appears to have the number 18 on it, which is totally appropriate for the celebration!

Hamilton like Hernandez gushed over Hansen, sharing, "I'm so happy that you walked into my life." Hamilton even apologized for being late with her birthday love on Instagram because she "was too busy twerking" alongside Hansen actually. Cabello, like Hernandez, shared a collage of photos of herself with Hansen. She then went into a long message like Hernandez and Hamilton did.

"CHINA JANE," Cabello affectionately began her birthday wish message to her 5H bandmate. She brought up how their joint name, "Caminah," as a tag on social platforms typically brings up "a series of gifs of me trying to hold your hand/lick your face/koala hug you/try to make you laugh."

These girls all have such an adorable sisterly bond!