sajda(prostration) is only for Allah Subhanahu ta'la!no doubt
but we do sajda on rauzae Mubarak of Aimmae masumeen a.s it doesn't mean that we assume them god it's an bowing down for respect
is it wrong?is it shirk?

Allah commanded the angels to make prostration to Adam (as) and this is not shirk. It is not a prostration of worship but one of respect.