I'm in my 20's and she is in her late 40's. I met her through mutual friends and from the start we clicked instantly. We go out all the time, spend time with her kids, a lot of things are done together. It seems as of lately though, she is starting to let the age difference get to her. Not once have I even mentioned the difference or brought it up. Maybe someone can explain that too me. I don't think it's a maturity level distance because otherwise we wouldn't be able to hold a conversation, let alone go out. Can someone try to give me some helpful advice? There is nothing more to add that can make my question anymore clearer. Its as simple as I say it is.

You are in two different stages of life and maybe she is coming to see that and perhaps it is embarrassing knowing people may be looking at the two of you and seeing her as either a cougar or your mother.
I know it would bother me and I can't see myself with someone as young as you. Maybe her children are bothered by it as well.
If she is backing away from you, let her. She knows what she wants and what she's doing.

You probably are missing a lot of little ways that you are different aside from maturity level.
They are adding up.
Plus she may have wishes for her future that are more immediate than yours are, such as a husband, and you are not ready for that. You don't mention the age difference between you and her children. I imagine they aren't that much younger than you?

I agree with your other two answers. She is old enough to be your mother, and if a relationship with 20 years difference in ages lasts, she will be 70 and you only 50! There really is too much difference.
Part of the problem is probably the maturity level. She has had 20 more years than you to experience life, do more, go more, and even make more mistakes than you.
If you will look around, you can find someone else, maybe not more than 10 years difference in your ages, or even younger. Good luck.

I'm not disagreeing with you. I am just trying to see how to go from here. I respect anyone's wishes, she just never said anything. I'm seeing hints though. So thank you, now I know where to go from here. Have a good day.

Her short, and long term goals are different and she looks for maybe more long term plans than you do. The fun is great fornow, but the future is closer to her, than yours is to YOU.