I started showing at about 8 months--in my
third pregnancy!
By that, I mean that no strangers noticed I was pregnant until then.
Oddly, I showed earliest in my first pregnancy; my husband & I could see a difference at about 13/14 weeks. But it wasn't really
showing, it was more the general shape my body was starting to take on. Your uterus doesn't hit the top of your pelvis until 14 to 16 weeks, if memory serves. So if you notice a difference before then, it is like to be a subtle one.
Of course, when it comes to being visibly pregnant, like anyone in the world notices it...like I said, 2 out of 3 pregnancies it didn't happen. I remember talking to my insurance agent's secretary about a month before my middle daughter was due and her being absolutely shocked when I told her just how far along I was. Which was nothing compared to her amazement when I brought my first daughter into the office!