How to make a hollow triangle with a star?

I want to construct a hollow triangle with stars on the borders.

desired triangle

n=7;

A = ConstantArray["", {n,n}];

For[i=1,i<=n,i++,For[j=1,j<=i,j++,A[[i,j]] = "*"]];

A // Grid 

I can’t do this with the code above. what should I do instead?