She might be transitioning to one nap if she's fighting it....3:45pm is also a little late in the day for a second nap in my opinion...how long are her naps for?
If you could push forward her bedtime to between 7-7:30, wake at 7am, with a mid day/early afternoon nap at around 12ish for approx. 2 hours... I think you'd be set! That would be 14ish hours of sleep in a 24 hour period (that's ideal in my opinion).....
One of the mods might have a different view...