I am looking at booking a cruise this summer for a family trip with our daughter who is 25, and sons ages 22 & 18. This will be our first cruise. One son wants to have time to include scuba diving at an island port stop. Looking at Oasis of the Seas. Any suggestions on lines, ships and itineraries?

We've booked NCL Jewel for ourselves with our 3 kids ages 30, 27 & 20. This will be the first family vacation since the youngest was 1 yo. The older 2 did not live with us.
We are going in May for 7 days FL, Great Stirrup Key & Nassau roundtrip from NYC. This will be the 1st time cruising for the older 2. There are many more interesting ports, IMO but we chose this because it will give us all a chance to relax together, enjoy the ship, beaches and any water activites without breaking the bank for us parents.
Hope you find a great trip. FYI, a lot of the cruiseline have posted that they will have price increases at the beginning of April if they have not already. It may be prudent to do your investigating and choose something soon.
Good luck! Have a great time together!