One more thing to add. My son turned 3 in December and I weaned his little brother from nursing back in September (around 13 months). Sometime in January my 3-year-old started getting a lot more snuggly/cuddly, saying things like, "mommy, I'm not your little boy. Hold me like a baby. Mommy, can you feed me like a baby?" My friend, who watches them, has a nursing 4-month-old, which is probably why he was asking about nursing. I realized that, while I play with them when I'm home, I haven't been spending one-on-one time with my older boy. We started trying to do things together, like leave Daddy home with the little brother while I took my older one to the store and out for a small treat or something. He also tells me every day when I get home, "Mommy, you can't go to work! Mommy, you need to be home!" They split their time mostly home with dad, who works evenings and is in school, and my friend with her children around their ages for a few hours a day, so they are not even away from us very much. He is very sociable with adults and children, so I'm not worried about anything, just realize that his "mommy" needs are changing, too. If you have your daughter with you while he is in nursery school, you might try to leave her with someone once or twice a week, or at least once a month, and tell your son that you are going to go do something together. He might feel as though you are doing something without him when he is in nursery school.