Oh wow I never thought of that. I thought they meant weeks!
I go between this forum and the 18-24. I'm 26 and feel like I might be able to answer some of their questions. also, it's out of habit that I go to the other as that's where I went during my last pregnancy. but if I have a question, I'll post here unless I absent-mindedly use the other.
It is by years, so you are in the right spot. Every once in a while, a moderator does a post to remind us, but I haven't seen one of those in a while. Welcome!