Bristol Palin Pledges No Sex Before Marriage

Bristol Palin, 19-year-old mom, said Friday that getting knocked up by Levi Johnston taught her a lesson, and she won't make the same mistake twice.

She told Oprah Winfrey that she's been depressed since the birth of her 13-month-old son, Tripp, and sees the error of her past, protection-free ways.

As a result, she vows to not have sex until marriage.

"I just think it's a goal to have, and other women should have that goal," the daughter of Sarah Palin (who was by her side) said of her chastity oath.

Oprah "bristled" at Bristol Palin pleding abstinence now. "Don't you think you are setting yourself up?," Oprah asked. "No, I don't," she responded.

Bristol Palin is Levi Johnston's baby mama. After that horrible experience, she vows she won't be someone else's. Well, unless that person puts a ring on it this time.

"I have a kid in my life, and it's my full-time job now," a melancholy Bristol told Oprah. "I have this big, supportive family and stuff, but I just felt so alone."

Her mom, vice presidential candidate-conservative TV pundit-celebrity baby pimper Sarah, said Friday "it was a shock" to find out Bristol was pregnant.

"Like so many other parents, I thought, 'not my kid,'" Palin said.

As we reported Friday, Bristol is seeking child support from Levi, her high school sweetheart, who scored a big payday with a nude Playgirl photo spread.

She's seeking $1,750 a month from Johnston, with whom she has a prickly relationship. A lot more than a box of condoms would've cost, Levi. Just sayin'.

By making a belated abstinence pledge, Bristol Palin is ...