When to start pumping?

Hi, my baby is 20 days old. I've been exclusively breastfeeding; waking my baby up every 2.5-3 hours to eat. I'd like to start pumping but my doctor says to wait at least a month so he won't have problems latching. Does this mean when I start to pump and bottle feed he will prefer the bottle over the nipple? I'd like to continue to breastfeed as much as possible til I go back to work, but would also like the option of a bottle. FTM. Appreciate any input. Thanks! : )