Men who prefer younger women, would you be OK with your daughter dating an older man?

I'm a man myself, and I generally prefer dating women 2-4 years younger than me (I'm in my late twenties). I don't really see my preferences changing when I hit my thirties - I'll probably still be most attracted to women around the age of 25, not only because they're physically more attractive, but also because they still have relatively youthful energy, aren't as jaded and are generally more fun to be around. This also gets me thinking though - would I be OK if my daughter was 25 and she was dating a 30-35 year old man, or even a 40 year old man? Maybe, but what if she was 18 and the man was 30? I have to admit that I would be a bit uncomfortable with that. What do the other men on here think? Especially those who prefer dating younger women. Would you be OK with your daughter dating someone considerably older than her?