Hi! My son is 18 months old and is taking one nap a day. He's been taking only one nap for about 4 weeks now. Since the transition, his naps are only about 1 hour long. He sleeps about 11 to 11 1/2 hours at night. I feel like he should be napping longer. What do you think? He puts himself to sleep, we have "black out shades" in his room and the neighborhood is relatively quiet. Any suggestions or advice ??? Thanks so much !!!!!!