it totally can depend on baby's position too. And some people just generally can recognize it earlier, I think.
I am 16 weeks and I haven't felt baby yet, I don't think. With my first it wasn't until 21 weeks, with my other two, around 17-18 weeks.
I felt DD at 18 weeks and this one at 14 weeks. 14 weeks is still VERY early from what I understand. Like the others said it's all just the luck of the draw...placenta placement AND baby position all make a difference. They are so small right now that it's no wonder you can't feel them. They are also growing at a phenomenal rate, so a week makes a difference of an inch or two in size sometimes...That goes a long way to feel them.
I know you're a worrier...but try no to. Honestly.