i think they are all different hun. My little boy is 14 months and is mostly having only one day sleep of anywhere from 1 to 3 hours. He also goes down at 7pm shattered and has been getting up later (waking about 7am but not ready to get up til about 7.30/8am)...

but he did this for a week or two, then went back to two shorter sleeps during the day and has now gone back to one sleep!!!

At 10 months he was doing 2 naps a day and 7pm bedtime til about 6.30am.

I think overall it's just how much sleep they are getting in a 24 hr period, some kids need more, some less.

If it's working for both of you, I wouldn't change it..... lol she'll change again soon anyhow, you know what they are like hahahaha.