Hello Renee,
The others who replied to you seem to have covered most points but I would just add that I took my first trip with Just You last year. I, too, belong to the older brigade, and it was my first trip abroad for over 40 years. (My late wife would not fly and I don't like boats.) I opted for a holiday within Europe and, once getting over the initial apprehension, had a marvellous time.
I suggest that perhaps you look for a not too distant trip as a first timer.
As the others said, the age range is very wide and varied from 26 to 80+ when I went. All got on exceedingly well and some firm friendships were made. I am off to Austria this year and really looking forward to it.
Go for it! You'll have a great time.
Mike