Does there exist a skew-matrix $A\in \mathbb{F}_3^{n\times n}$ with det$(A)\not=0$ and uneven $n$ ?
We can use det$(rA)=r^{n}$det$(A)$, for what it's worth.
I would be gratious about a hint in the right direction.
I would myself solve it with writing out the determinant, but that seems very tedious with unknown $n$.