Study on a dependent pass

Dependant visa... Masters?
Dependant visa is only for children under 18 years old.
If over 18 years old, that will be long term social visit pass.

For Dependant visa under 18 years old, there is "permission to study".
Application for the "permission to study" can be made to the immigration office.
Please check with your school on this, whether permission to study is good enough or they require their students to get student pass.

OR, you will have to cancel dependant pass and apply for student pass.
Malaysia immigration does not allow one person to have 2 visas.
So, if you are under dependant pass, your student pass application will be returned/ rejected.
For student pass, just reach out to your school, they will sure have someone to handle student visa.