Y axis seems inverted with Ortho Matrix?

I'm trying to understand projection matrices and I'm messing around with a ortho matrix in OpenGL and it seems like the Y Axis is inverted.

I have a simple square on the screen made using this vertex data:

float size = 32.0f;
float zIndex = -1.0f;
vertices[0] = 0.0f;
vertices[1] = 0.0f;
vertices[2] = zIndex;

vertices[3] = size;
vertices[4] = 0.0f;
vertices[5] = zIndex;

vertices[6] = 0.0f;
vertices[7] = size;
vertices[8] = zIndex;

vertices[9] = size;
vertices[10] = size;
vertices[11] = zIndex;

indices[0] = 0;
indices[1] = 1;
indices[2] = 2;

indices[3] = 1 …