Did you ever hear of Princess Diana you idiot?
'Princess' was not an official title for Diana Spencer (like it is for those born in line)....
she was called HRH 'Princess off Wales' which was just a created honorary title/style given to an outsider.
Kate Middletons daughter is a real deal 'Princess Charlotte' having been born in the royal line.
Kate Middleton herself (as H.R.H. Duchess off Cambridge), is not officially titled a princess.
Sarah Ferguson (as H.R.H. Duchess of York) was not titled a princess.
Camilla Parker Bowles ( H.R.H. Duchess of Cornwall) is not titled princess.
Royal line princesses are that at Birth.
