As a young person you have your rights according to the policies that govern our land of Malawi. You have a right to say no to early marriage and it is against the law to be forced into one, especially when you are under the age of 18. You can choose to do what is right for you and according to the way you have asked it seems as though you want to continue your school and not rush into marriage.
If someone is attempting to force you into marriage I would suggest that you take the matter up with a relative, trusted elder person or even close friend who has your best interests at heart and can help to speak to those who are asking you to undertake marriage against your wishes. If the matter persists then you should cosider taking more formal action and reporting it to the relevant authorities.