Am I feelkng flutters?

I'm almost 18 weeks pregnant but haven't felt baby move yet. I know it doesn't happen right away & have read that sometimes it takes first time moms longer to notice. But I have been feeling flutters toward the left side of my abdomen kind of where my ribs are. When I was at my OB and heard the heartbeat, she found it on the left as well.. not as high as the flutters but on the same side. Could these be baby flutters or am I imagining things? I have no idea what it's supposed to feel like!