I have been fortunate to cruise many times, with many different lines, both with and without kids, friends and family. What your travel agent told you is true, as a general rule, Celebrity's average age is slightly older than the other lines you mentioned. However, considering when you are sailing (Jan. 10th), the average age for most any cruise line is going to be higher, as it is just after a vacation time and most children are back in school. So, no matter what line you choose, will most likely have far fewer children than normal - and, since most of the major lines all have good children's programs (some better than others, but still all good), I would choose your cruise based on value and what appeals to you, as opposed to choosing for the kids. Knownig that no matter who you cruise with is not going to have many kids on board, and taking everything you said into consideration, I think you choice of the Mercury for your time frame, is a very good value on a very good cruise line. (I have not been on the Mercury, althoug am sailing her on Jan 3rd, but have been on many of Celebrity's other ships). The only other suggetsion I can make, is to look into a Category 6 outside cabin vs your Cat. 5. For what should be a very minor difference in price, I believe you get a far better deck location. Best of luck in your decision, and happy cruising.