She's not too old for rocking.... I wish my older girls would let me rock them (they're almost 6 and almost 4).
It seems to me like the real problem is that the bedtime routine is just way too long. A good bedtime routine really shouldn't go longer than a half hour, or Mom gets burned out pretty darn quick! You will make your life so much easier if you cut out the tv watching and the snack. Rock her while you read a couple of books, then, while you're still rocking, sing her one lullabye (Rock-a-bye, or whatever), and put her to bed. That is really all she needs for a good solid bedtime routine.
I only say that because I used to do the same thing with my girls. The bedtime routine used to last almost 2 hours! By the time I was finished kissing them goodnight, it was after 9:00, and I had no time to really get anything done for me, which led to extreme Mommy Burnout!
So now with my girls, the bedtime routine starts around 7:00 and ends by 7:30. We first brush teeth and go potty one last time. Then we go into the girls' room and read a scripture story and say prayers. Usually by then, it's 7:30 and they go to bed. Occasionally, if we get finished earlier than 7:30, we'll read another book or two, or we'll talk about what dreams we're going to have when we go to sleep. But they're in bed by 7:30, and I'm out of the room by 7:35, and I have the rest of the evening to do whatever I need to do.
I highly recommend simplifying the bedtime routine, but don't cut out the rocking.... it won't be long before she won't let you rock her anymore, and then you'll be kicking yourself for cutting it out early!