When did your baby first started to hold his/her bottle?

I'm a first time mom..& my baby boy is 8 months old and still doesn't wants to hold his bottle. I have to put a blanket under his bottle so he can drink it..he held his bottle one day but ever since that day he stopped. I told his doctor but she said its normal..I tried to make him hold it but he just starts crying until I put his blanket under his bottle so he can drink it..I don't know what else to do..if you have any tips it would help a lot..thank you in advance