You could harvest the tops frist if your planning on taking the rest down in next few days allow them some extra time thoe I'd wait for an even amount of good buds through the centre of the plant then harvest, but if your tricomes on plant are ready chop her at your preference of high
Looks like it could be ready but you should be checking the trichomes to be sure though. You can always cut the top colas first then let the rest of the plant continue to mature.