how much older than you should your man be

i hear hear a lot of people saying that if you are the same age as your man you never respect each other but i don't think that's true because who have respect also respect others but the only reason why i would like men to be older in a relationship is because women grow faster than men. the moment you have a child you grow more so women should be younger at least 3 years younger than their men. what do you think