That does sound small for two months. Next time start a little earlier and give it some good veg food to grow. The plant should be fine in a five gallon pot until it get a little bigger then I would transplant it. And you should of transplant it during the veg so leave it there for now. For now flowering time has started and with a 6'' plant I don't think your going to get much. Still try some flowering food and sugar.
Good luck