most infants transition to whole milk at 12 months assuming they are eating well from the table and do not have any sensitivity to milk and milk products. milk is just one source of nutrients in a child's diet but cow's milk and soy formula are not bio-equivalent. i don't know why your child is on soy so i really can't give you the "okay" to start whole milk. you will need to talk to her pediatrician.
my 11 month old drinks soy formula can i switch her to whole milk