M.S.
M.,
Sleeping patterns do change with toddlers. Sometimes it is because of a change one can pinpoint, sometimes not. You mentioned that the routine during the day is the same. I'm wondering if she is taking multiple naps during the day? It sounds like perhaps she could drop a nap and/or wake up earlier? Also, is the television on in the evening? There is documented evidence of the stimulant-effect of the screens of computers and TV.
Also, it sounds like there are 6 of you in the home, with every one else having a later bed time than your daughter. I know that for us, we had to adjust OUR schedules to help our son get used to going to sleep earlier when he started to school; we also made an additional change of not turning the TV on during the school week.
Best wishes and Merry Christmas!