Yep, it's normal!
This is very similar to what happened to us, except Ollie was doing fine for his morning nap and refusing his pm nap. We switched him on to one nap (at around 13 months) and for the first couple of days he slept longer than ever. Then the naps got shorter and shorter.. we got down to around 45 mins. Then he started waking really early in the morning (5:30am for example). Then he started waking up several times during the night and taking ages to get back to sleep. Welcome to the wonderful world of OT!
However, I do think this could all have been avoided, so a few words of advice:
1. The early bedtime is KING! Don't be afraid to put her to bed before 6pm if she needs it. From what you've said today it seems like 3.5hrs A time in the afternoon is still quite a lot for her so maybe make that your rule.
2. Don't see this as a jump to one nap, but more the start of the transition. Just because one nap has been the right thing to do for the last couple of days, it doesn't mean that you can't do two naps tomorrow if she wakes earlier in the morning.
3. Be prepared for the transition to last a couple of months. At the moment, there are not enough hours in the day for her to fit in two naps with the A times she can handle BUT there are still too many hours in the day for her to cope with only having one nap. They kind of have to grow into it as they head towards 18 months.
4. Be flexible. If you do what you can to ensure that she gets the sleep that she needs then you may be absolutely fine. But if you don't pay attention to the signs you can very quickly end up in the land of OT, which is not a nice place to be, right Leslie?
Fingers crossed it all goes smoothly for you
