She's not a real princess since she only showed up in a sequel. There's certain criteria they have to meet to be considered as official.
"Each Official Disney Princess must:
A) have a primary role in a Disney animated feature film,
B) be human or closely human-like (i.e. Ariel), and,
C) not appear primarily in a sequel. The actual title of Princess (or equivalent) is not necessary, but certainly helps."