I don't think I'd want to date someone who is way older than me. I figure about ten years tops. I don't really think I'd want to date who's a few years younger than me, either. Really though, I'd have to listen to God's guidance on it, then make a concrete decision.
I do agree with the others, though. I think maturity is a major element. I don't want to date someone who's a few years older than me, but acts like my twelve year old brother. I would look at their maturity - spiritually, and intellectually. I don't mean that he would have to be a genius when I say that. I mean like common sense and such.
I guess to answer your question, I reckon it's not as big of a deal with me as it is with others. I would prefer to date someone closer to my own age, but if God has other ideas, so be it.