Is Breast Really Best??

My son is going on three years old and still attached at the...mammary gland. He loves nursing. Loves it. At about two years, I was thinking he "should" stop, "should" wean, and "should not" be so attached. But then..why? I mean, what's wrong with him still wanting my milk? We adults still drink milk so why wouldn't he still want milk? Aside from social norms, why would he need to stop? And so this journey of gentle weaning has begun. I want to sleep better and so he must sleep better for that to happen so for that reason, I've weaned him off the nightime feedings. But aside from that, I've decided there's just no good reason to stop until he's ready. My breastmilk has literally grown his brain, his bones, his BODY from his infancy and I just can't see how it can hurt. So what do you think? Have you felt pressure from society?? Let me know your thoughts!