Weeks, Months, Trimesters

I will be 30 weeks pregnant on Wednesday. Easy enough right? What is so confusing is how that translates into months and trimesters.

I've been thinking that since I am due on November 9th, that on October 9th I'd be 8 months, and on September 9th I'd be 7 months - putting me today at 6 1/2 months pregnant. Then I read a friend’s Facebook post that is due at the same time and she said she is at 7 1/2 months. So confusing!

So I looked it up. Is this right? According to the chart below, I am days shy of 30 weeks, nearly 8 months and in my third trimester. Not that it really matters, but all of a sudden I feel a lot further along.