The point is her implied view on judgmentalism. From the article:
What message does she want to send to other teens about premarital sex? "I definitely don't think it's something you should do; it's better to wait," she told the magazine. "But I can't be judgmental because it's a position I put myself in."
If you really deconstruct that statement, she is saying she needs to avoid making a statement about sexual morality/responsibility because such a statement is, by definition, "judgmental." In essence: "How can I be 'judgmental' (i.e. make a statement about morality), when I have put myself in this situation?"
I know it's just Jamie Lynn Spears, but her comments really are a reflection of a common, simplistic assumption: A statement about sexual morality is inherently "judgmental".
We commonly attack others when when what they say makes us uncomfortable about our own life choices. We don't stop to think whether he/she is being judgmental or just rational and maybe even loving.
Here's a link to the article: