It is interesting to me that you are experiencing this because, I have had men of all ages who have been attracted to me, asked me out, want to talk to me, etc. until I tell them how old I am. Once I do that, they seem to hit the brakes and then everything ends. I only started experiencing this once I turned 40. I am now 42.
Now, I do pause a moment and say to myself, that I must not look as old as I think I do because they never seem to realize my age until I tell them. But then I get over that brief ego trip and move on to realize one thing: In the dating pool of attempting to hook up with someone we have a shelf-life. This means that the younger we are as adults the better it is for us to date casually, to learn the kinds of people we want in our lives, who we don't want, etc. It means we have to date a lot when we are young. So, my question to you is, are you trying to hook up or are you trying to find a life partner to connect with? If you are looking for a life partner, then age is not going to matter to the type of woman you want: a woman who is partnership material.
No one told me how short our shelf-life is for casual dating, so I did the wrong thing and worked while going through higher education. Now it looks like I may have missed that window of opportunity. Plus, I was never interested in casual dating, per se. I wanted courtship then marriage and children, even as a young adult. But to get to that place with someone you still have to be in the presence of lots of people in order to figure out the kind of partner that is good for you...that can help you work through whatever residual effects you have from childhood, life; and vice-versa for that person.
To answer your question it usually is not a turn off for most women to have slightly older man ask her out. Maybe about five years older. My new cutoff is now 10 years because I am already 42 myself and would like to have children. Most men I know want to be somewhat agile with their kids. I would recommend increasing the age of the women you ask out. Most young women are still trying to figure themselves out, what they really want, how to balance their lives. Plus our society has the roles so reversed for men & women, that most young women now have no idea how a man should really even be treating them. A lot more people who are younger than our generation have grown up without a balance in the home: meaning a nuclear family. So increase that age and see what happens with slightly older women. Good luck to you.