Likely so. Think of your daughter's sleep as totals for the day. My son, Emilio, fifteen months sleeps a total of about thirteen hours a day, two hour nap normally and eleven at night. Sometimes even a three hour nap, but that often leads to a wee bit of a later bedtime, hence reducing nighttime sleep some.
Some babies easily nap longer with reduced nighttime sleep. Some seem to wake regardless... if yours ends up being the latter, try wake to sleep in the midst of her nap to extend it. Have you done this technique before. A gentle rubbing of her tum, etc. just enough to get her to roll over and come out of a deep sleep. It will jumpstart the sleepcycle and often leads to longer sleeps.
With my boys I always just went sorta cold turkey with things rather than gradual and their temperaments allowed me to do so. So, if she's relatively easy-going, I'd just wake her at 7:00 tomorrow and have a go at it.
Let us know what happens, eh?
