[K. in Cleveland]

OK, I have a couple of points I thought of while reading your post.
I myself am in a relationship in which there is a lot of age difference (22 years). If two people are matched in personality and interests, and sense of humor and yes, physically, then age doesn't really matter. It took some time for me to get used to the ides that when I'm 40 he'll be in his 60's and so on and so forth... But now it doesn't matter because I love him so much and I want to spend our lives together.

Yet, when you went on in your post, talking about how she goes back and forth.. it sounds to me like she either enjoys games or she's emotionally unable to commit. Do you know how long ago she lost her husband? She sounds like maybe she's going through a stage of her life where she feels lonely but is not sure she wants to start all over again. Especially for her, she's almost 50, she's probably afraid of starting a serious relationship again, especially with someone so much younger than she is. She may also need some counseling if she is still dealing with grief over her late husband. This can be a major hurdle for relationships. Some people never fully move on from a loss like that, especially if they were married for a long time. Also, the fact that you remind her of her late husband may also be presenting an emotional challenge to her. She's probably thinking, "Do I love him, or just miss my husband?"
My best answer would be to muster up the courage and tell her exactly how you feel, and that you don't care about the differences in your ages, and just be honest.
You might get rejected, but then at least you'll know. That not knowing can be weighing you down. If you know there's no future relationship here then you can move on.
But if it all works out, then who can say anything about it? It isn't about anyone else, it's about the two in love (no matter what their ages are).

Just be open and honest and it will go the best. I hope she can give you the same respect and be open and honest for you.