Credit: Instagram

It seems like just yesterday that Maci Bookout was 16 (going on 17) and pregnant! This OG Teen Mom gave birth to her adorable son, Bentley, almost five years ago, and we can't believe how much he's grown up. No seriously, consider us shocked.

Not only is Bentley a professional motocross racer (that's right, little dude drives a dirt bike all around the dirty south), he's super smart and he's about to take a big step in his education! Yep, Benny From the Block is starting Pre-K this fall, and Maci's mind-blown by how fast the time has whizzed by.

"My son is starting pre-k..." she posted to Instagram on August 5. "Im so proud of him, but man i feel a meltdown coming soon. #bigboy."

Wow, can you believe Bentley is already starting pre-kindergarten? Kids these days … they grow up so fast! Clearly, this is an emotional time for our girl Maci, so we're thinking she should comfort herself with a brand new pair of Chucks and a few more coats of bright orange hair dye.

Before she knows it, Bentley will be graduating elementary school with honors and getting a BA in Monster Trucks!

Are you shocked by how quickly Teen Mom's cutest kiddo has grown up? Maybe Maci should pop out a few more babies to fill her empty nest … or not.

Source: Instagram