I'm in the middle of the month this time, but when I was pg with ds, I was due August 25th (and he ended up being born September 1st). Like 3pink1blue suggested, I spent time on the September board as well as August, because that way I felt less "behind". It'll be especially helpful when the babies start coming, because there may be some "October" babies who come 8 weeks before other "October" babies. And when you're one of the last ones, it can feel like the early moms are sending their babies to kindergarten by the time yours finally shows up!
That being said, though, the difference isn't so big in the middle stages of pg. There'll be several months where you probably won't feel very "behind". It's more at the beginning and end. And, of course, we're all glad you're here with us!