Hi,
Is there any way to change my username I want to use my last name instead of my middle name is that possible?
Sure just
profile
then username(In my case; KittyKora)
preferences
There is no edit button 
You clicked onto it
You where suppose to acces it see example bellow
Maybe this link will help you: http://forum.freecodecamp.org/u/ahmedmoataz/preferences/account
if you state what your new user name should be a mod can make the change for you