Throughout this season of "Teen Mom 2," we've seen Kailyn encounter — and conquer — one major life change after the next. She moved to Delaware, married the love of her life, Javi, in front of all their family and friends, and continued to co-parent son Isaac with her ex, Jo, despite their many differences. Oh, and she did this all while being pregnant with her second child. NBD.

Finally, after what seems like forever — but, in reality, was only nine months — Kailyn is ready to give birth and Javi is right by her side to support her through it all. In this sneak peek of Tuesday's episode, viewers catch a glimpse of the couple and Kailyn's friend, Peach, heading to the hospital in the wee hours of the morning.

While Peach hangs tight in the waiting room, Javi's in the delivery room with Kailyn, rubbing her back as she deals with painful contractions. Then, after 16 long hours of labor, Lincoln Marshall makes his world debut!

When big brother Isaac lovingly holds the newborn for the first time, he turns to his mom and says, "Look! He's a baby!"

Kailyn then explains that both he and his little brother are her babies, but Isaac argues back, saying, "No! He's my baby."

WHY IS ISAAC SO FREAKIN' CUTE?!?!

What apparently wasn't cute? Little Lincoln's hair, which Isaac says is "disgusting." Hey, kiddo, that baby just traveled a pretty long way. He can't help it if his locks are slightly mussed.

Check out the video, and tune in Tuesday at 10/9c to watch Baby Lincoln's first day home with his fam.