Close in age is great at a young age, it's when they hit their adolescents and teenagers years.. my 4 and 2 year old get along pretty well my 12 year old girl and 10 year old were best friends till a couple years ago, now they are enemies... my 8 and 7 year old girls get along great still, however I'm waiting.. My unborn is a boy so I'm excited to see how the boys do close in age down the road...