In the words of Prof. Wolfe at MIT in response to the idea of maturity in men, "Good Luck".

In all seriousness, don't worry about age so much. Age isn't really that great an indicator of maturity. I have worked with 18 year olds who acted like responsible adults, and worked with 40+ year olds who acted as small children.

Don't ignore a guy just because he is a little younger, find out if he really is mature. By the same token don't fall into the trap of an idea that guys of a certain age are going to be more mature. It is amazing how often that fails to be the case.

All in all, judge each on an individual basis.

Also the comment about being up front about what you want is a good idea. If nothing else it will save you some time and problems of having to deal with guys who don't fit the bill. Go for the type of guy you can be happy with, don't "settle" for someone who isn't going to work. Keep trying and the right guy will come along, one way or another it will happen.

Best of luck.