Is 43kg underweight for an 18 year old girl who is 4 foot 11 inches?

well im 12 and i weigh around 58, and im pretty small, but i dont look fat,

if u keep eating and try and make ur self the right weight it can block up. everytime u eat, dont exersise. just chill for a bit.

Well I'm not so sure, im 12 and weigh 43kg but I'm around 4 feet too.