Since $\dim M=0$ we have $\dim A/\operatorname{Ann}M=0$, so $A/\operatorname{Ann}M$ is a local artinian ring and you are done.
Since $\dim M=0$ we have $\dim A/\operatorname{Ann}M=0$, so $A/\operatorname{Ann}M$ is a local artinian ring and you are done.