It was at one time that being a full member, senior member, etc had to do only with the number of posts you'd made. It has nothing to do with how long you've been a member of the forum. I think it's bugged now though, it's not updating regardless of how many posts have been made. Don't quote me on that.
Thats what I was wondering if something was wrong, because some were full members that didn't have as many posts as I have. Not that it makes that much difference, but I had just noticed that and was wondering.