At 11 months old should I start introducing whole milk?

My daughter is still pretty adamant about having her formula bottles. She drinks about 24 oz of formula a day and gets fussy if she doesn’t get her bottle. I end up giving her a bottle before every nap and before bed to get her to sleep because she has a hard time winding down without it. She knows how to drink out of a cup, but ends up spilling a lot of it. I’m not really sure if I should start trying whole milk yet or if I should just wait until she is a year old to start weaning her off. We just moved so I need to find a new pediatrician but any advice is appreciated. Thanks!!