My Daughter is almost off her formula!

Since my daughter will be soon 11 months, I am starting to mix up some whole milk to her bottle. Actually I am doing a 1/2 whole milk=1/2 formula milk ratio with her. I just want her to get familiar to the whole milk while making sure that her tummy will be able to digest the cow's milk. I know most moms would do it until they reach 12 months. But I found out from a certain mom's group that it will be alright to start her early, so that once she reaches 12 months, she can completely be off formula. Definitely, it will be a good thing to us since we can save some bucks by not buying the formula anymore which ordinarily she would just consume for a week compared to the whole milk which is a lot cheaper. Evidently, I am still making sure though that her nutrition needs and welfare are taken care of.Besides, she eating enough solid foods that helps to balance her nutrition requirement.