Yeah, I think it was my height that held me off a bit with the girls. Being my 3rd & the little bit of a belly I gained between DD2 & DS would've been the reason I started showing a bit earlier.
I remember I was about 24 weeks when I went to visit my Grandma with DD1 (when I was at my skinniest 54kg due to severe m/s) & she aked my Uncle after if I was pg & said she thought I was only about 4 months.
We have very straight grandparents, so kept it quiet for a bit as I was only 17.