i did the same sort of thing as you a few years ago. It takes absolutely ages to grow cos of the lack of intense sunlight. Took me five months to get a bushy three foot tall plant, but it was still no where near flowering. Then i moved house and my parents wouldnt let me transport it in the car(obvious reasons i suppose) so it went on the compost heap!
Just see what happens mate. water it when the soil gets properly dry as Mj is used to pretty dry climates with a big downpoor every so often. (look at Morrocco)