If you're above average height it might me harder to tell. My friend is 6ft. And her belly is still so small at I think 26w.
I have seen many women on the thicker side, that has HUGE baby bumps(: Good luck to you , remember you are just starting.
Girl I was 245 lbs when I first got pregnant and I have a huge baby belly lol everyone always asks me if I'm having twins
Yah cause I'm chubby and I'm 32+4 and I have a baby belly