It depends on the person. Everyone's belly grows different. I started showing at 9 weeks... he was growing at a fast pace, so at 2 months my belly looked like it was 4 months etc..
I didn't start showing till about week 26, and I'm 28 weeks now, started out as a plus sized mummy too...
I started showing at 24 weeks, one week I was a twig, the next I was a whale, lol.
Yeah because I'm 27+4 and i just start showing but i was really little when i got pregnant
Give it till about 18-20 weeks