20 weeks with my first haven't felt a kick

Jen
I'm 20w1d with my first baby girl. I've felt what I believe are flutters but I'm not sure. They feel like they could either be gas or almost muscle spasms. I haven't felt anything on the outside just yet and I'm starting to get nervous. Everything looked normal on my last ultrasound on the 19th. My next ultrasound isn't until the 22nd of November.