I think it's great that you are going to travel. You need to treat yourself.
They have some awesome groups and travel tours specifically for single women over 50 (as well as ones for men and all other age groups). Many of them are for adventurous and young spirited women. I've heard of women going solo and making lifelong friendships.
I would definitely check out this woman's blog about solo travel Girl About the Globe. It is an excellent resource. They have a detailed page with all of the reputable tour companies for single women over 50.
It won't let me post the link because I'm new. But you can just type Girl About the Globe Solo Travel over 50 into Google and it will take you right to that page.
That blog also has a Facebook group. Fb groups in general would be a great place to get more info. If you are on Fb.. I'm sure there are a bunch. I'd search Facebook Groups for phrases like Solo Travel, Single Women Travels, Traveling Over 50, etc.
Happy and Safe Travels!