Nothing to worry about. Position of placenta, extent of bloating, your general fitness/health etc. are all things that can effect how and when you being to "show". Congratulations!
Thanks and yeah, it probably depends on how the baby is lying also. I'm actually hoping it means this baby will be smaller then the last *lol* My first was almost 10lbs :)
For me, I'm at about the same rate as with my first child. I haven't shown any sooner, which I though would happen. So I would say, yes, it's possible. Each pregnancy is different, I would assume that applies to all aspects.