I think it's really different for everyone and everyone carries differently. Some people can be tiny and still not show for ages and some bigger ppl show really early!! So there's no predicting it, lol. And I know, you really wanna know when you're gonna get that gorgeous bump!!
For me, this is my 1st, I'm 158cms and was 52-53kg, and I was showing by 12 wks. Now, you can't miss it.