Questions about Gossip Girl the novel?

It has reference to sex, but no intimate scenes. It has a few curse words here and there, mostly 'bitch' and a few insults. I started from book 5 and I didn't seem to miss a lot, the books always give a subtle summary of what has happened so far. It's not direct, but you'll get it as you read.
I can't really remember the idea of the first two books, but they were really good. I read them when I was 12. After you finish the Gossip Girl series, check out It Girl, it's like a follow up to it. And also the tv series is completely different in some way. It's like two different stories. Anyways, have good fun reading the books.