How to stop elderly from making comparison of babies? Find it irritating and sickening for giving comments like "other babies can alrd do this and that, yet urs still cannot, dumb dumb one or why so slow"

This kinda mother tak boleh tahan. Like as if you are not stress enuff. I mean they should know every baby got its own timeline for development. I am quite garang lah, so I just tell my mother/mother in law to mind their own business and not piss me off.