I was about 100 lbs heavier than you the first time I got PG. I didn't start showing until about 5-6 months. Here's a pic.

Although with clothes on I definitely looked PG but if I looked at my belly, it just looked bigger.
Here's one of me at around 8 mos.

And although I still had the two bellies, you could tell that there was a baby in there too.
With my son I was showing by 4 months and people could tell I was PG and I weighed over 300 lbs. at that time.
With this PG and the last one I miscarried, my top half of my belly started pooching out around 6weeks. I've even lost weight this time around and my jeans aren't fitting well and I'm just over 6 weeks.
HTH.