20 weeks and 4 pregnant?

I'm 20 weeks and 4 days pregnant with my first baby and I have been feeling this weird felling under my belly on for about a week now it stays in the same place and I didnt know if that could be my baby or would I feel it all over its kinda hard to explain what it feels like its kinda like a jerking feeling or maybe the baby fliping I am really clueless to all of this