Why is my daughter fighting sleep?

My 27 month old daughter recently has decided to kick her night time routine out the door. Until her second birthday, we used to get her bath in at 7:30pm, in her pj's just before 8pm with her teeth brushed, read for about 30 minutes and she would be out by 9 or 9:30pm. These days, even though we wake her up at 7am, she will not go to sleep until well after 11pm. She will fight, scream, cry, kick, just to get back on the couch for a few minutes and than try to play and color. The lack of sleep is causing me to become depressed. How can I get her back to her routine??????????