Have just started showing at 20 weeks. First time probably the same, however I got a job at 7 months without them guessing. But that's coz Im tall, the bubs sit towards my back.
I looked pregnant today, but that was after a big yum cha meal. People may have thought I'd just been extra greedy!! However, I have not been able to fit in my old clothes for about 10 weeks at least!!!