I have a 20 month old who has recently started refusing to go to sleep til after 10 pm. He gets up about 7.30 and naps for an hour and a half in the day. By 8pm he usually starts to look sleepy. But if we put him in his cot he just seems to become suddenly no longer tired. So we end u getting him back up and putting him to bed at 10pm, when he settles without much trouble. Does this sound like he is ready to give up naps altogether? It seems a bit young? I can't help wondering if he is actually overtired.