Is it a cardinal sin to build a greenhouse with the roof running North/South, rather than the recommended East/West?

I have a 100ft long North/South facing garden, which is extremely narrow on the East/West axis, just 17ft wide. As I wish to acquire a 12ftx8ft greenhouse, I would not have enough space at either end for access at the entrance and for cleaning glass at the ends etc.

The only viable axis is the North/South one - is it really such a big deal to have the length facing east/west?

It will (for the forseeable future due to funds constraints) be an unheated greenhouse in which I plan on growing winter salads, raising seeds/cuttings, and summer tomatoes, chilis etc.