Pregnancy?...
That varies from one person to another, so we can't give you a definite answer.
It depends a lot on your size, the position of your uterus, and if you've been pregnant before - but even all of that can't foresee it.
If you are quite slim then around 3 and a half to four months. My friend is pregnant and she started showing at fourteen weeks. This does vary from person to person though.
with my first I didnt show till 5 months. I started showing at 2 1/2 months this time.