Will my baby wean herself or do I need to?

Yes. This depends some on the dynamic the two of you have going. Some kids need more nurturing than others so try to recognise ques on time to change. Some are so interested in exploring when they begin walking that you find yourself chaseing them down to feed--time to transition. If baby seeks you out for feeds, enjoy it (for breast) but put water in bottles >1yr. They will toss it & accept a sippycup.
Depends. Dr ferguson's answer is right on.But a bit more specific is that some children will not wean on their own, because the nipple, either breast or bottle is a pacifier. Thus they may need to be coaxed.However there are babies that will wean on their own.Just need to see where yours fits in.
Yes. You have to wean the baby from either the breast or bottle. This should start at approximately 9 months of age by using either a sippy cup or a small liquor glass.