This is actually an interesting question and I'd like to comment on two things.
Personally I have never liked the whole concept of "dating" (as in: socially meeting another (relatively unknown) person with the prospect of considering them for a future relationship). It is something that I would never feel comfortable with; I like to meet new people and socializing, but not for the sole purpose of entering a new relationship. Of course this is a personal thing and something that depends on personality and such.
As for age differences, that is a difficult one; I know people who, despite a large difference in ages, have working longtime relationships, I also know couples who split up even though there was only a few months' difference in age. In other words, in my opinion, the difference in age is not a deciding factor in a relationship. However, I'd make one exception and that is a relationship where one of the partners is under-age (this will differ from country to country) and the other is an adult.
I'm pretty straightforward on that subject, but if two people decide they want a relationship and one of them is under-age, then IMO they should keep it at friendship until both are of age, or if that is not an option, break it off at once since their relationship likely has no future anyway if one or both partners are not able/willing to build it up slowly.
I also don't think it will hurt anybody to slowly build up a relationship; if you want it to last there really is more to it than falling head-over-heels in love and living on a pink cloud.
Because being under-age may differ from country to country I really have no particular opinion on the ages expressed in the first post, and in my view there are other much more important criteria that'll determine whether or not a relationship "works" (although there are of course certain practical implications, for example, if one partner is 57 and loves hiking, they need to realize that their 78 year old partner might not be able to join them in that).