You are concerned about maturity which is not always dictated by age even tho age is usually an implication. So, it doesnt have to strictly be a certain age gap. I personally like to date girls around my age because they are more mature and emotionally stable and better yet, they know what they want. You cant effectively tell someon3s age irl unless u ask and u oftentimes find out there is a gap but still like em based on their personality.