Ready to grow the family – but under time constraints! Tyler Baltierra and Catelynn Lowell just welcomed daughter Vaeda three months ago, but they’re already talking about having more!

“We would love to have a boy one day,” Lowell, 27, told Us Weekly exclusively, adding they’ll probably wait until their daughter turns 2. However, that doesn’t mean the couple will continue trying until having a son.

“If we’re meant to just have girls, I guess that’s what we were meant to have! I’m not going to have like, six, or seven kids – no thank you,” she laughed. “I feel like I’m already going gray with two!”

Baltierra, 27, and Lowell welcomed their first daughter, Carly, in 2009 and placed her for adoption. They also share 4-year-old daughter Nova. However, the Conquering Chaos author has a timeline for future children.

“By the time we’re 30, we’re done. He’s getting fixed, that’s it,” she told Us. “I already told him. I said, ‘I carried all three of your kids and birthed them and pushed them out of me, you’re getting snipped, sorry!’ And he’s OK with that! He’s like, ‘Yeah you’re right, you did carry all my kids and have to go through labor, so. [I’ve] got no choice!’”

For more from Lowell, watch the video above and check out the latest issue of Us Weekly, on newsstands now!

Teen Mom OG returns on MTV Monday, June 10, at 10 p.m. ET.