Ahoy, Candi!
I am so glad you navigated your way to the Disney Parks Moms Panel to ask your question about your first Disney Cruise! You are correct that your sons would be divided into separate clubs onboard.
The
Edge is a club geared for "tweens", ages 11-14. There are some high-tech activities, as well as fun group games. When my oldest visited Edge, they had a movie night and a scavenger hunt. The
Vibe is a teen club, geared for ages 14-17. The teens get a special sticker on their Key To The World card that allows them access to this club, and others are not allowed in (even parents), except during open house times.
On your embarkation day, there are usually open house hours in all of the kids clubs, so that families can go and check out these areas together. I would encourage you to bring your sons to both of them, and also urge the boys to go to the first evening of activities in their respective clubs. This is the time where the counselors will play "get to know you" games and plan some activities for the week with the input of the kids. It has been our experience that the clubs might let a thirteen year old into Vibe, with parental permission, as long as they are not at their capacity for that week. It is something you could ask them at the open house. I do not think they would allow your fifteen year old to go into the younger club.
I wish you the best as you embark on your first Disney Cruise Line voyage! Please come back with more cruise planning questions.
Happy Cruising, Tracy V.