Hi gillykaren,
I'm in my early fifties and did two just you holidays last year after losing my girlfriend :-
1. Americas golden west (june), 18 of us 7 men and 11 ladies with ages ranging from 27 to 77. I was the 2nd youngest man but would say half the ladies were younger half older.
2. Tresures of andalucia (november), 45 of us 10 men and 35 women, similar age range to the previous trip but quite a lot more at the older end, think that was to do with it been at a cooler time of year.
From what everyone tells me that are JY veterans virtually every trip there are more ladies than men so don't think you would be alone.
I had a fantastic time and made good friends on both trips as I'm sue you will. In fact I've just booked for my 3rd JY holiday to Mallorca in april.