I would talk to your pediatrician first, but my daughter (who is now 2) weened herself at 11 months. She just lost interest in breastfeeding. I was told that it was okay to put her directly on whole milk (up to that point I had been exclusively breastfeeding also)
The one struggle we had was that Nora took a bit of time before she really took to the cow's milk. She had a three month period when she did not gain any weight or grow (she has always been very small) .. That was a bit scary.. but then she took off after that!!
I also transitioned her to a sippy cup right away with the whole milk.
Good luck. Don't you wish these kids came with instruction manuals?
E.