I am 18 weeks and on my 3rd pregnancy and my first to I left move early on 14ish weeks. But this pregnancy I too was feel baby move up until the beginning of my 18th week. And this one's a boy! Goes to show all pregnancies are different no matter the number.
Firstly, what is your weight like? Are you a big momma? A lot of stomach mass might just be cushioning baby's movements so you don't feel them yet. I did a scan at 13weeks and while we were at it,baby waved a hand and kicked out. I didn't feel them but I and my doc saw the movements. Don't worry, baby is already moving a lot more than you know :-)