Given that her father was Ptolemy XII she was literally a princess and is described in such a fashion. Even though her sister Berenike IV was next in line (not counting of course her brothers Ptolemy XIII and XIV) she was still a member of the royal family and possible claimant to the throne. Following the execution of Berenike who had briefly usurped Ptolemy XII Cleopatra was made coregent at the age of 14 but this was mostly a formality as it is unlikely she wielded any real power at this point in her life.

But was she a princess? Absolutely, she was the daughter of a king, raised in a royal household, and from a rather young age slated to share the throne with her brother. By the way, may I ask what prompted this question?