I got a gradual belly although i thought it was massive but no one else could see it. By 20 weeks i had a good sized belly and you could tell i was pregnant and didn't eat too much cake at morning tea! By the time i gave birth at 38 weeks though i had a massive belly and everyone thought i was having twins. Enjoy having a little belly for now as when its big it is big!!!
It is frustrating how everyone has an opinion on the size of your belly when your pg. Everyone either says too big or too small. No-one seems to say just perfect. In one night last week I got told I don't look pg at all by about 3 different people and another couple asked me if I was having twins because I was apparently really huge for 19 weeks. I just had to laugh it was so ridiculous.