Leah Messer got candid about the first time she had sex.

On Tuesday’s episode of “Teen Mom 2,” the reality star revealed to her friend Kylie how young she was when she lost her virginity.

“I cannot believe my kids are 10. I was 13 the first time I had sex,” Leah, 28, confessed. “The girls are 10. Granted, I did not get pregnant until later. I’m saying it’s confusing.”

“I didn’t know anything! I didn’t know anything,” she added.

Leah shares twins Aliannah and Aleeah, 10, with her ex Corey Simms. She also has daughter Adalynn, seven, with ex-husband Jeremy Calvert.

As for tackling the topic of sex education with her young girls, Leah said she would like them “to know everything and know what happens.”

“Not just, ‘I don’t want to be like you, ma.’ Okay, but why?” she added.

Kylie chimed in and said, “But I think your atmosphere growing up was way different than their atmosphere. Yours was obviously not that great, so I don’t think that that’s something you have to worry about. But you’re right you have to let them know about things. Be honest with them.”

During a birthday party for the twins, Leah turned to her daughters and exclaimed, “You guys get to learn from my mistakes, right?”

“You’ve made some big bad mistakes,” Aliannah replied.

“What do you mean I’ve made some big bad mistakes?” Leah retorted. “Getting pregnant at 17 wasn’t a mistake, it was a challenge. I didn’t know what the heck I was doing, but I made it work and look at us now.”

“Teen Mom 2” airs Tuesdays on MTV.