Did I feel the baby move???

I've never been pregnant before, so I have NO idea what the baby moving is supposed to feel like. Before last night, I felt fluttering in my uterus every once in a while.

Last night, shortly after hubby and I went to bed, I felt... I don't know how to describe it. Like, a flipping in my uterus area, if that makes any sense. Something shifted and COMPLETELY changed the way my abdomen felt. It shifted the pressure that was there. As I said, I don't know what it's supposed to feel like when the baby moves, especially this early on, but I can't think of anything else that I can possibly chalk this up to. I didn't have gas. I didn't have to use the bathroom at all. They say thinner women tend to feel movement earlier than heavier women, but after years of feeling different pains and having to differentiate between them I'm also very in tune with different sensations in my pelvic area.

I'm excited about the prospect that I may have felt the baby move, but I've heard you don't really feel that until 16-20 weeks. I'm 14.5 weeks now, and I know he's been measuring about 3 days ahead (so we'll estimate his size at 15w1d), but he's still not as big as he would be at 16 weeks. Any ideas???