I saw your other post about your kids staying together................they will be in different age groups. I know the older one will be in Club02 (ages 15-17) and the 11 year old in Camp Carnival (I think it's ages 9-11). I realize you would like them to stay together, but as a mom with 2 boys who were in different age groups twice, I can tell you that they will both make friends their age and have a blast! Your 11 year old won't be able to go up to the 15-17 year old group, BUT, the 9-11 group has so many things going on, he's sure to have a good time. It also gives your 15 year old a chance to meet friends and do his own thing.
It's very important that they both attend the meet and greet, for their age groups, on the first night. You might have to attend with your 11 year old, but your 15 year old can attend by himself. My younger son was 11 on our first cruise and, unfortunately, the meet and greet was for 11 and under and parents. It was mostly small kids, but we went in anyway, and he found another 11 year old who he spent the rest of the cruise with, adding kids to their group as the week went on. It really helped that he found a friend the first night. So, even if the meet and greet doesn't look "cool", give it a chance, and help your son find a friend if it doesn't happen on it's own. (the 11 year old we saw was with his little sister and parents.....we all went over and said hello; I told him Jason was 11; he said his name was Joey and he was 11; that's all it took--
Also, they won't spend each and every minute in the organized activities so they will have a lot of time to spend together too. Just make rules for both of them, so you can check up on them and also have time to relax with your husband.
Have a great cruise!