Thanks for the compliments. The members of cruise-chat love helping new cruisers. It is great that you came here well before your cruise so we can help you. Every so often people will show up here who didn't bother to ask questions beforehand, and their first post is a rant about something they didn't understand or like. We don't like those posts. Nothing we can do after the fact!
Swimming with the dolphins is a great tour. Just make sure it is the right one since they have many versions. Most are really an "experience" (like the $110 tour you mentioned) where you stand on an underwater platform and get a few seconds here and there with the dolphins. Mostly you just watch them go through stunts. You need to do the tour that has you actually out in the water with them. It is always much higher in price.