There is no real way to predict when or if your daughter will "self-wean". I breastfed my son for 9 months. He loved the breast, didn't care much at all for the bottle. I worked one day a week and on that day he would refuse a bottle from my husband, so I just knew that he would be very hard to wean. Much to my surprise, this wasn't the case. At around 8 months, he gradually started to lose interest in breast-feeding, i.e. playing alot during feedings, looking around instead of really nursing. So, I just dropped one nursing session every few days and he was just fine with this. I personally know of other children who were still nursing at 2 years old, so each child is different. Only time will tell how your situation will unfold. Having said that, I do think that it is wise for you to teach your daughter now how to fall asleep on her own. Children develop sleep associations, whether it be nursing, a paci, a bottle, a special lovey, etc... I am a firm believer that children learn how to fall asleep by themselves, so that if they wake up for any reason, they will be able to put themselves back to sleep too!
Ultimately, you have to do what works and feels right for you and your baby. Pediatricians recommend that we nurse at least until 12 months of age, but this is no magic number; there isn't going to be a switch that goes off in your daughter's head when she turns one that says "I don't want to nurse anymore." She may stop before then or she may want to do it a lot longer. The rule of thumb is to stop nursing when either you OR your baby loses interest. Hope this helps!