Hi Ted,
I think you will find many cruisers in that age group, as to if they are single??? Be sure to read through the paper they put in your cabin each day and look for any of the singles gatherings, there will be some. Just attend them and be out and about and you'll sure to meet people, hopefully you are sitting at a large table for dinner, better chance to meet more interesting people and have great conversations.
I'm sure you will have a wonderful time, just relax and take part in activities that interest you, enjoy!