With my first one i didnt start showing till i was 7 and a half to eight months pregnant. I ended up with an 8.6 pound baby, with this pregnancy I started showing at around 3 months, and im still small. So yes it is very normal for a first pregnancy not to show very much until you're further along. Especially since you were small to begin with. Good luck with your little one!
Im 35+1 and can still hide my baby bump its normal with your first baby:)
This is my first as well and i just started showing and im 34 weeks n 4 days...people always told me i didnt look pregnant but every pregnancy is different..