When did preemie start Bottle feeding ?

I know that every baby learns at their own pace but I wanted to know when anyone else baby started bottle feeding , my LO was born at 35 weeks and 3 days gestation and now he’s around 37 weeks gestation and still barely taking his full feedings and when he does it’s like the nurses up he’s cc intake then it’s back to square one or they don’t bottle feed him every feeding they’ll tube feed him which I feel like he’ll never learn that way 🙄