It doesn't matter but we must agree that the gap poses a problem. The likes and dislikes differ, the other 'older' person may listen to something more mellow while the other something totally opposite. That kind of relationship will require more efforts if you ask me. More efforts of understanding each other and being patient.
I think it only matters if the maturity gap is too wide (speaking of legal age). I'm dating 20 years older now, but we have similar interests, hobbies, and the same ideals, so we never even notice the difference. Then again, I've dated guys a single year older and they either were too "fuddy-duddy" or too immature for my tastes. As long as there is a lot in common, and you're pretty much at the same level of maturity....the age difference won't even be noticeable.