How much can i grow in here - first grow

OK so first off I've just decided to imaginarily grow weed, and this is all hypothetical, a "what if" scenario if you will. I have a closet shown in the diagram, and only a portion of it am i planning on growing my plants. This area is on top of a shelf in the upper-right corner of the closet, and has no ventilation. Will the lack of ventilation be a major problem? About how many plants could I grow in this thing?

Thanks for your hypothetical imaginary advice.