Graphing a Normal Vector to a Plane from the origin

I’m trying to plot a normal vector to a plane. I know I’m doing something I should know better, but can’t seem to find. Vectors {0, 1, 2}, {1, 1, 3} obviously determine a plane. Their Cross Product is {1, 2, -1}, which is normal. Unfortunately this code (all from the origin):

Graphics3D({{Blue, Arrow({{0, 0, 0}, {0, 1, 2}})}, {Red, Arrow({{0, 0, 0}, {-1, -2, 1}})}, 
{Blue, Arrow({{0, 0, 0}, {1, 1, 3}})}})

Yields,

enter image description here

Which doesn’t look quite right. Just don’t trust pictures? Any thoughts appreciated. Trying a different way I found some Mathematica code from a multivariable course for normals to a plane… and I got the same thing…