Aww congrats mama! Usually around 16-20 weeks ka na magfe-feel ng movements, pero kung ito talaga ang una mong pregnancy, baka mas huli pa dahil hindi mo pa alam ang exact feeling, some of my mum friends thought kicks lang ang flutter sa simula kaya hindi nila napansin! The spinning/rolling sensation you're describing sounds like baby gymnastics, which is so sweet, and it means your little one is active and growing well na, so enjoy mo na yan habang nandito ka pa sa second or early third trimester.