Credit: Twitter Photo: Corey Simms Takes Aliannah and Aleeah to See the Easter Bunny

How time has flown! And no one knows this better than the Teen Mom parents. To think it was just a few days ago we were watching pregnant teens on 16 and Pregnant, and now their kiddos are all grown up taking selfies with their moms and dads on Instagram and Twitter.

Speaking of Twitter, Teen Mom 2 star Corey Simms’s father, Jeff Simms, took to Twitter today to announce a special anniversary of 16 and Pregnant proportions:

4 years ago, Corey told me Leah was pregnant. Then he said they were having twins! I about fell over, can't imagine life w/out them now,” Jeff tweeted on May 24. Aww!

We can imagine how shocked Jeff was to receive news of his son having not one, but two babies on the way, but he definitely got over it. The proud grandpa has endless photos of his twin grandbabies, Aliannah and Aleeah Simms (who are now 3 years old), all over his Twitter.

And even though Corey and baby mama Leah Messer’s relationship didn’t last, the Simms family seems to be really close with their former in-law, who’s just as friendly with Corey’s family and new fianceé, Miranda.

It’s pretty amazing how things have changed over the course of four years.