Very often, you will see a mid 20 year old female dating a 40 year old male or a 30 year old female dating a fifty year old male. What do these males have in common?
Experience
A 40 year old male should have enough experience that he makes very little mistakes in life in terms of leisure activities, finances and knowing what he wants. This security is attractive to females because she can rely on him to help her reduce mistakes and offer direction and insight she would not know.
So does this mean you need to wait until you are old enough? Of course not, age is not the factor. It is the experience, the knowledge and the success that turns her on. So to gain experience, you simply have to accept more stimulus. Staying at home and watching T.V. won't cut it. Go out, explore, try new things, learn new ideas and discover. The more you know, the more value you can add in an interaction.