By no means am I an expert, as we are still very early into the 1 nap a day transition at 15 months, but I think a few things I have learned during the process, may help. If your dd is waking before 6am, and not napping until 1230, this seems like a pretty long A time for being relatively new to 1 nap. Will she go down any earlier than that? She's giving you a great nap, which is awesome, but because it's so great and starting a bit late, you then end up with a really really long day....like 14 hrs. I'm still trying to wrap my head around this concept myself. My LO would give a great 2 hr nap and be happy all the way til BT, but because her day was always too long (due to being a chronic early waker) it would just reinforce the early waking. Another revelation I have had just recently, was having to limit the nap to no more than 2 hrs. Here I was finally getting long naps, but still only getting 10-10.5hr nights! In the last week, I have limited the nap to 2hrs, and we are now inching toward an 11hr night....although it's still an early wake up, as we are going to bed between 630and 7pm. Like I said, this sleep thing is a total mystery to me, but maybe some of these suggestions could help.