Movement?

For all those mommies who have had more then two kids I have a question. Is it possible for me to be feeling movement when I am only 13 weeks?
It's not all the time...obviously. But every once and a while I feel something on my left side that resembles the little fluttering of a baby. Phil thinks I'm crazy.

Emma I didn't feel until I was 17 weeks, Ethan I believe was around 14 or 15 weeks. I can't remember exactly because I don't have his pregnancy journal with me but I know it was much earlier than with Emma.

I am just wondering if this is even possible.

I would say yes only because I have been pregnant so many times and now know what to look for. My uterus has probably "thinned" a bit from all the pregnancies making it easier to feel. I know the baby is small....about 3 cm right now but the way I see it is that kidney stones are milimeters and you can feel those suckers. Phil says "well yah but that's in your urinary tract." and I said "so it's my uterus...it's still inside me what's the difference?"

So he thinks I am totally batty but could this be possible?