"It had been a very long time since we had been on the show," Bookout tells PEOPLE. "I wasn't getting recognized everywhere I went anymore and people didn't really care. It was very quiet."
So when the network approached the now 23-year-old to appear again on the hit series, she wasn't sure if it was the right move.
"I was definitely apprehensive," she says. "But I thought it was really cool and all of us are in such different places in our lives that it would be nice for the fans to see how much we have grown."
Now as Bookout prepares for the birth of her daughter with boyfriend Taylor McKinney, the Chattanooga State college student is busy balancing her full-time career as a social-media-marketing specialist and being a mom to 6-year-old son Bentley.
"He's so excited for the baby," she says of her son with ex Ryan Edwards. "And I'm excited for him to have a sibling. I think it will be good for him to finally have to share the spotlight."
And as far as her once rocky relationship with Edwards? It's no longer a big issue for the former pair.
"We don't argue with each other," says Bookout. "I guess we just learned it's just not worth the energy, and we've grown up a little bit."
With just 11 weeks until their first daughter together is due, Bookout and McKinney are busy making plans for their future.
"We definitely want to get married and we've talked about it a lot," she says. "But we aren't trying to cram it all in at one time. After the baby comes and we get settled in with parenting two children, then that will definitely be our next step."
Teen Mom OG premieres Monday at 10 p.m. ET on MTV.