well judging simply by your leaf structure it appears your growing a sativa, or a hybrid which is sativa dominant. Sativa's typically take longer to flower and yield slightly less than indicas but with a more up high(like a mind fuck rather than couch lock). Now bare in mind I say typically, it is not always the case plant for plant and strain for strain but somesativa strains can take 12 - 13 weeks to fully mature and flower. Your plant appears healthy and happy, it may have been stressed from light leaks and growth has slowed, it may be strain specific but as long as it's happy just keep doing what your doing and harvest when it's done. It will tell you its done when the pistils turn red/brown and curl in and your trichromes appear amber or cloudy. Good job, sativa is my personal favorite due to sleep apnea always making me incredibly tired most weeds knock me out and I don't enjoy it. Enjoy yourself and keep growing!