PS=protective styling, which essentially means keeping your ends protected and off your neck, shoulders, places where it can snag, etc.
Some people get great growth without doing it, but since you've indicated that you've been at the same length for 3 years, that may very well be a source of concern for you.
My hair isn't fond of olive oil either. I find it to be super greasy. Try a lighter oil like grapeseed or sweet almond. They can also be found at most health food stores (I haven't found them in my normal grocery store) and see how that might work better. Grapeseed was too light for my hair, so I used it for my body and to cook. Good luck!