Tevye from Fiddler on the Roof said it right when he told us that tradition is how we keep our balance. It helps us know how to navigate the world. It makes things easier. It can, of course, also be stifling, outdated, and just plain dumb. In "Girl," Mom teaches Girl tradition for many reasons. Tradition helps her to become a proper lady. It also keeps bad luck from finding her. Isn't an endless to-do list a small price to pay for the warm embrace of tradition?
British tradition is just as important as African tradition in "Girl." Both are important elements of Girl's cultural heritage.
Food is the most important part of tradition in the text, because it is connected with the lessons of femininity that Mom is passing along.