I think it definitely depends on the woman. I'm 30 weeks now and have gained 13.5 lbs. I'm not showing very obviously. I wish it were totally obvious that I'm pregnant as I fear my baby belly can easily be mistaken as a food belly at times. I've grown weary of people telling me I don't look pregnant (because I figure that just means I look like I've gained weight)! I was a size 8 pre-pregnancy and now I'm around a size 12. A coworker of mine (whose about my same pre-pregnancy size) is due just 2 days before me and she has a beautifully distinguished baby bump. It's also her 2nd child and this is my first. I've read that makes a difference. Now that is a month after your original post, Angelia, are you happy with the size of your baby bump?
I didn't start looking full out pregnant till about 27-28 weeks and it seemingly happened over night and now I'm 30 wks and look like I'm almost ready to pop lol. I've heard it depends on if you're a first time mom or not and body size. I'm a first time and very small. They say FTM take longer to start showing and to get big.
I am 26 weeks now and showing with my little boy. You can tell unless the shirt is huge at this point but im not very big either it feels like maybe 4 inches out belly wise at this point. For me around 22 weeks it was about half of what it is now and i didnt look pregnant i had just started showing bump wise and only people that know me could tell.