Also please note that you do not need, and should not use the MY_API with structs. That is for exporting class functions. If you need such functions you should be using a class, not a struct.
As long as all the code is in the header file, there is no need for a typedef to define whether or not it´s exported, since all the code is right there in the header file.
Given your statement that you are an experienced C++ developer, that is something you should be aware of already.