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.

A photo posted by DinahJane (@dinahjane97) on Jun 22, 2015 at 12:59am PDT

1997 A photo posted by DinahJane (@dinahjane97) on Jun 22, 2015 at 1:03am PDT

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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!

A video posted by Normani Kordei (@normanikordei) on Jun 23, 2015 at 3:21am PDT

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, let me just come right out and say that everybody and their mother knows im obsessed with you. if you look up the caminah tag, it's really a series of gifs of me trying to hold your hand/ lick your face/ koala hug you/ try to make you laugh. i am like hopelessly in sister-love with you and it's pathetic. but here's the thing everyone. if you knew Dinah you would do the same thing. because this woman is damn magical. does it make sense to thank you for being you? because I am so thankful to God that you are you. i am so thankful for 3 am when you're so exhausted you can't even keep your eyes open and you listen to me cry and tell me everything's gonna be okay. i am thankful for those nights we've seen each other absolutely broken and we've had to hold each other to not fall apart. i am thankful that we are each other's sword and shield. even if we're annoyed at each other, you will defend me to no end and have my back if anybody messes with me and i the same with you because we believe in loyalty. you trust me with your secrets and i trust you with mine. i am thankful for when i need you to be my wingman and you tell me "YOU GOT THIS WALZ" and when I'm your wingman and I tell you- and l will say it again and again- that you are the most gorgeous, talented, kind hearted woman any man that approaches you will ever have in his ENTIRE life and if anybody tries to take away your smile (btw have you seen Dinah's smile? it's like a unicorn) but if anyone tries to take it away I may be small but I CAN KICK. kind of. well I'll do it for you china. i am thankful that today a real life poly princess was born into the world and her name is Dinah jane Hansen and it is the most beautiful thing to see How much she cares about where she come from and speaks up for the poly community with such pride in her eyes. today you were born and I received the gift of true friendship, of loving someone so much your heart swells. you mean the world to me China. i love you forever, walz A photo posted by camila_cabello (@camila_cabello) on Jun 22, 2015 at 11:54pm PDT

"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!

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