I'm a first time mom too. I'm 23 about to be 24. I wasn't tiny before my pregnancy but I wasn't fat. I started to show around 12 weeks, which is odd. It really just depends on where you carry at. Some moms, like me, carry farther forward, when some moms, like you, carry farther back. You will probably start to have a belly soon.
This is my 3rd pregnancy abt to b 23 weeks n just started showing but it looks like I just over ate. No round bump yet. Baby is measuring big at 2 and a half weeks bigger. But having a big belly is not all that. It'll just cause more back pain. N stretch marks. But no showing doesn't mean the baby isn't growing. I rather show little as possible. Besides it's the last 3 months of pregnancy that it's will show up.
I'm 22 wks and started showing around 20 wks when I just looked like I had a slight tummy because of not working out. I think you'll pop out very soon...you might always have a small bump as it depends on lots of things...where your baby is lying, how strong/stretched your muscles are and where the placenta is. Perhaps plan a gender reveal party for when you do find out...that will get you more excited. I think things will start to change very soon for you and very quickly too!
With my first pregnancy I didn't start showing until I was 24 weeks, and even then it was hard to tell. I "popped" around 28 weeks. This is my second pregnancy and I'm 21 weeks and have been showing for a few weeks now.
Maybe wear clothes that show it off more. With certain clothing I just look fat. Im 24 weeks now. Didnt really show for a long time and all of the sudden I had a big belly. That I didnt even noticed untill my dad pointed it out..
If it makes u feel better i didnt have anything really untill 20weeks. It practically popped up over night. now 21 +4 and still dont think im that big. Alot of people dont believe im pregnant at all. Still dont no what my baby is but hopefully will find out on sat.