That is a very popular itenerary. You should have no problem with it. Some people report that Jamaica can be a little frightening. I've heard reports of open selling of drugs on the streets, and some would say aggressive locals. The local authorities are trying their best to clean up the crime, but they have a daunting task. You will find people who will never get off the ship there, and you will also find people who love the place. My advice there is to treat it like you would going into any large city.