I grew up in Malawi and I know that parents like to teach their children to work hard by asking them to do chores around the house or even do a little work in the farm, there is nothing wrong with that, it is a good thing to learn how to pitch in at home. I do not know your family’s situation but I hope that working on the farm does not mean not staying in school.
Unfortunately, sometimes we forget that teenagers need their adolescent years to discover themselves through school and fun activities. But in most cases youth are not given that time to discover who they are, rather they are being expected to help around with household chores. It is encouraging to see that things are slowly changing and am hopeful that in a few years adults will be more understanding of teenagers.
But in your case Madalitso it would be good for you to talk with your parents, tell them of your interest to stay in school. You can contribute by doing household chores after your studies. If you feel shy about it ask a relative, your teacher or any other community leader such as a member of a Mother Group to talk with them on your behalf.