Just as a design hint. Do not use an initialize function. Initialize all the things in your constructor. Otherwise a user might forget to call initialize and the code does not run as expected.
The use of constructors for this purpose in an arduino context is not appropriate. There is initialization of the hardware which must be complete before code such as serial.begin will work correctly. You should expect that the constructors will be executed before this init code. This is why so many Arduino libraries have a begin method to do the job that you might use a constructor for in a different environment.