You will have a wonderful time and Oceania is a good choice.
The island of Tahiti is ok but the outer Society Islands are what will give you that true tropical paradise. I hope you have some overnights in the itinerary. A great way to see Bora Bora is to rent one of the small cars (basically a golf cart) and explore the island. Stop by the roadside stands and small markets and restaurants. You'll have a ball. I agree with Jean that it can be a bit expensive so plan on eating your breakfasts and dinners on the ship but do try some of the local food for lunch. Or just grab an assortment of tropical fruit from a roadside stand and have a wonderful lunch.
Ask locals where the best beaches are and go there. There is some FANTASTIC snorkeling and diving so make sure to try. On Moorea we rented a car for the day and stopped at a very small, rocky beach that had some local families swimming there. It didn't look like much but it was one of the best snorkeling experiences I've ever had anywhere. BTW: Topless is normal for the beaches so don't be offended.
You will think 10 days isn't long enough.