Battery

Why does my new macbook air 2020 drains so fast? My mac is just 2 weeks old to be exact and has a 14 cycle count. I always keep it plug in all the time while using it, is it okay? Then i tried to use the battery one time on a full charge, i thought it would last 12 hours? Btw i’m just only using facebook, but after 3 hours the battery drop down to 60% already.

does anybody has experienced that? Hope you can help me with my concern.