yea, I would transplant it to the larger pot.. as a rule, a 5 gallon pot per plant is good.. it will double in size by the end of the flowering stage so you dont want the roots to get bound.. Im surprised though that you were trying to flower so early, I've never heard of a plant successfully moving into flowering stage after only 2 weeks of life! It depends a lot on genetics BUT I would say that if you put the plant in 12/12 after the end of the 3rd week, then the fourth week they should show pre-flowers and then by the 5th week they should start flowering.. I must say though that forcing flowering too early leads to stress which leads to hermies and/or males.. good luck!