Is OOP the right approach always?
Nope.
When OOP is the best approach?
When it helps you.
When OOP is a bad approach?
When it impedes you.
That's really as specific as it gets. Sometimes you don't need OOP, sometimes it's not available in the language you're using, sometimes it really doesn't make a difference.
I will say this though, when it comes to technique and best practices continue to double check what your professors tell you. Just because they're teachers doesn't mean they're experts.
