Jenna is ready to have sex with Jake. And she just happens to tell the whole school that in this scene.
Matty offers Jenna advice on handling her first time with Jake on Awkward. "What Comes First: Sex or Love?" is the sixth episode of the second season.

Awkward Season 2 Episode 6 Quotes

Lacey: I am sorry we got carried away with all of that girl talk. I did not mean to embarrass you.
Jenna: Don't worry it wasn't the first time.
Lacey: And it won't be the last.

Jenna, contrary to the advice I've been giving Ally; you need to know that every first time is the first time, and it should be special.