I follow the same timeline
I am 27 weeks pregnant and I go by this chart I found online. It's the most accurate one I've found. According to it 27 weeks is considered the start of 7 months. Your First Trimester: 1st Month = Weeks 1,2,3,4 2nd Month = Weeks 5,6,7,8 3rd Month = Weeks 9,10,11,12,13 Your Second Trimester: 4th Month = Wks 14,15,16,17 5th Month = Wks 18,19,20,21 6th Month = Wks 22,23,24,25,26 Your Third Trimester: 7th Month = Wks 27,28,29,30 8th Month = Wks 31,32,33,34,35 9th Month = Wks 36,37,38,39,40