Why did she ask in front of everyone? Did she expect you to breastfeed in front of everyone or something?! 
It’s just typical desi aunty foot in mouth syndrome… does she know what’s in the bottle? Expressed breast milk or formula, either way, people won’t know. Next time, just humour them and say it’s breast milk in a bottle… and that you don’t want to breastfeed in public.
Unless the surgeon did a really bad job and damaged the areola, breast tissue or nerves, the incision for the implant is made in a fold below the breast and should not really interfere with breastfeeding. Oh, but then there is the whole saline vs. silicone debate… whether that makes a difference to your future lactating ability.
I guess everyone is different and are affected in different ways. Good luck to you anyway 