What does 要不不留学要留学就要留出个性 mean?
要不 / 不留学 / 要留学就要留出个性

"otherwise / don't study abroad / if you study abroad you should do it with personality"

or more idiomatically:

"if you're going to study abroad you should do it with personality, or not at all"

Note that 要...就要... is a common grammar pattern.