What's the Name of That Book??? discussion

I read this book in 2012 and it wasn't new, probably been out at least a few years. The author was a woman and has written more than a handful of young adult/coming of age books.
Main character was a girl, senior in high school, top of her class, all about school and no social life. She has a best friend who slept with an older boy in their freshman year and had a horrible nickname ever since. She uses that story of her friend to warn younger students in school to not be known for promiscuous behavior. That kind of behavior gives boys the power to define who you are, what you are worth.
Then she starts secretly hooking up with a popular boy in her class, and worries about what people would think if they knew, especially her mentor. A freshman girl who the main character used to babysit doesn't agree that flirting and hooking up with guys is necessarily bad, shows the main character that in a way it gives girls power.
*Dresses up as Amelia Earhart for a school dance
*Has a hickey on the day of senior pictures
*Her secret boyfriend lives on a Christmas tree farm and his mother cans jam and stuff

Not That Kind of Girl by Siobhan Vivian?

Yes, that's it! Thanks, I had it stuck in my head and couldn't find it online.

You're welcome Miranda.