My 3 year old son will only urinate and have bowel movements in the potty when he is at pre-school or if he is runnning around naked at home. If I put him in Pull-ups or real underwear he will urinate or have a bowel movement in them. When I ask him why he doesn't go potty when he is wearing underwear he tells me that he doesn't know he has to go. Needless to say how can that be? My other son was 4 yrs when he was completely potty trained. Am I trying too soon?