Ahhh the confusing part of first pregnancy kan! At 21 weeks, honestly boleh jadi baby movements dah tapi still very light and fluttery, macam butterflies atau gelembung air dalam perut, so memang susah nak distinguish from gas. A few of us tried tracking when the movements happen (like after makan or bila tengah relax) and realized certain sensations memang repeat-pattern, tu lah baby gerak, tapi if it's just random one-time sensations, probably just angin jer lah. Jangan worry, in a couple weeks movements akan jadi clearer and stronger, so you'll know for sure! For now enjoy the moment, next few weeks akan confirm 100%