AceShowbiz -

Is carrying a bun in the oven at merely 16-years-old, Jamie Lynn Spears has been all over the news with her shocking revelation to OK! Magazine that she's pregnant with boyfriend Casey Aldridge's child. Her interview with the publication won't hit the newsstands until Wednesday, December 19, but here's a sneak peek on it.

Is 12 weeks along, Jamie Lynn told OK! she learned the pregnancy from an at-home test and subsequent doctor visit, saying "It was a shock for both of us, so unexpected. I was in complete and total shock and so was he."

Initially decided to keep the news to herself, she revealed "As soon as I found out for sure from the doctor, I took two weeks to myself where I didn't tell anybody. Only one of my friends knew because I needed to work out what I would do for myself before I let anyone's opinion affect my decision. Then I told my parents and my friends. I was scared, but I had to do what was right for me."

It was not until the Thanksgiving holiday that Jamie Lynn informed her mother Lynne Spears about the pregnancy. Was shocked and very upset when she first heard the news "because it wasn't what she expected at all," Lynne however "had time to cope with it and became very supportive" at the end.

"I didn't believe it because Jamie Lynn's always been so conscientious," Lynne told the magazine. "She's never late for her curfew. I was in shock. I mean, this is my 16-year-old baby."

Much contrary to her very-early impending motherhood, Jamie Lynn said she believes teens should stay away from premarital sex, telling OK! "I definitely don't think it's something you should do; it's better to wait. But I can't be judgmental because it's a position I put myself in."