Hard Time Transitioning Off Formula?

Any other moms having trouble transitioning their babies to whole milk? I have been trying to gradually add 1 oz of whole milk with 4 oz of formula to my baby’s bottle. She definitely notices and will only drink 1-2 oz instead of her normal 4-5 oz. She only turned one on the 17th, but I feel pressure to get her off formula. She eats well and only drinks 15-18 oz a day so I am not afraid of her filling up on formula and not eating.