'My Girls': Briana DeJesus Shares First Photo Of Daughters Nova And Stella

'Teen Mom 2' sisters!

Shortly after Briana DeJesus welcomed her second daughter Stella Star, the new Teen Mom 2 cast member gushed that firstborn Nova was very excited to be a big sister. And the first photo of Bri's little ladies bonding certainly shows that their mama knows best.

Bri's girls! And would you look at that huge grin on Nova's face? That is one beaming older sibling.

Briana -- who gave birth to Baby S on Sunday and will document her second pregnancy when the long-running series returns on July 17 -- shared another closeup glimpse of her "StellyBelly":

As well as those tiny newborn feet:

And, again, a very proud Nova (appropriately modeling a T-shirt touting her brand-new role):

Be sure to offer your congrats to Briana and her loved ones -- and check out a glimpse of what's to come on the upcoming Teen Mom 2 season (premiering on Monday, July 17) in the first look below!