Usually when you are ask to write about your family, do you usually have to write about yourself too?
Not necessarily. You can choose one member of your family to write about, or you can choose a particular incident involving your family.
When asked to write about your family, it depends on the specific instructions of the writing task or the context in which it is being asked. In some cases, you may be specifically asked to focus on your family members and their background, without including much information about yourself. However, it is common that when writing about your family, you would naturally include some information about yourself as a member of that family as well.
If you are uncertain about the scope of the assignment, it is always best to clarify with the person who assigned or requested the writing task. They will be able to provide you with specific guidance on what they expect to be included in your family writing.