movement?

When did you mommas start feeling baby move, or have you yet? With my son I felt it at 15 weeks but wasn't really sure what it was till the next week when it started happening more frequently. I'm 13 weeks now and my mother thinks it's absolutely impossible that I may have felt the baby move, I'm still not totally sure and it's only happened a few times. Just curious on when you mommas felt your little ones move!