Harvesting Lower Branches first?

I have some AK-47 9 weeks into flower and the top main cola's look immature eg: small bud formation and 100% white hairs. I had heat problems between week 3 and 7 sometimes the heat got up to 33-34 degrees, the lower smaller branches and bud look a lot better and trics are cloudy, if I start harvesting all of these lower branches will it be ok, I don't want to stress the plant out. Does anyone know if the rest of the plant will mature, I flushed 6 days ago so I plan on giving no more nutes, just ph'd water?
Thanks in advance.