It's  official - Bristol Palin, crowned the Teen Prego Queen on Good Morning America. Do as she says - not as she did....

She's on the road as official ambassador for advocacy group to prevent teen pregnancy.

First stop - GMA in NY where she belies her own mishap claiming abstinence is "best" i.e. not having sex.

"Regardless of what I did personally, I just think that abstinence is the only way that you can effectively, 100%, full-proof way to prevent pregnancy," Bristol said.

Uh - what were you and ex- Levi doing?  Rhythm section?  And that coupling did produce their son - Tripp.

In her first live interview on ABC Bristol back tracked from what she told  Fox News previously that "abstinence wasn't realistic' as she girds her loins for inevitable custody battle with ex-fiancee Levi Johnston, 20.

Backtracking? Stonewalling?  Changing her tune? Well, Bristol IS the daughter of a politician - Alaska Gov. Sarah Palin.

And she'll be at her first town hall meeting at The Times Center in Manhattan for the Candies Foundation as a "keep it in your pants" advocate to teen sex fiends.