52 days (coming on 8 weeks) is a short time, but not unusual for an auto to do her thing. You can even have plants of the same strain, in the same grow, at the same time, with all the same-same everything, develop weeks apart.
All topping did for you was get rid of smokable dope. The side branches might have gotten a little bigger, but topping removes the money shot. It does not create two new mains like topping fem/photos.
Another glance at your plant, what do you mean by 'topping?' It looks to me like you cut the sides and left the main.
Another glance at your post, there is much experience around here with auto light schedule. 12/12 is what you want when you want to get your fem/photos flowering. Autos do better if you stick to 18/6. Flowering marijuana loves light. The more the better. You also never need to worry about providing darkness for autos. Open tent, closed tent, lit room, dark room. Autos will flower regardless of light and do better with more.