Welcome to you,
I have been on 8 JY holidays but NONE off the Christmas breaks have family here that need feeding! not sure they want me to go missing at Christmas. There are many threads on the boards about new people to JY so have a look around at then there are a couiple of video links from Cindy and the Lovely Lesley so that might help you as well.
I do know from talking to people when I have been away that the Christmas and New Years breaks can get booked fast, so bare that in mind.
At the 39 you would be in the younger aged bracket but if you have your eye on a tour you can ring the office up and ask the age range, they will give you an idea or post on the editor boad on here and BEN wil give you an answer.
I am under the impression that the new main brochure is due out middle September so I would think the Christmas brochures will be out then as well They will be live online then as well.
I hope you can find something that appeals to you.
Happy travelling
CIndy