Six months old? How big? If shes already hermied she'll start growing seeds pretty quick. You CAN take her to finish.....but I'd worry about spreading pollen to your other plants even if you keep her in quarantine.....just sounds like an accident waiting to happen but that's just me.

If you do finish her and IF she has a lot of seeds (which it sounds like since she herrmied early) your yield will be fairly reduced so its your decision on whether to finish and get what you get or not. A six month old plant sounds big so it might be worth doing just for that reason alone. I probably would NOT finish the plant myself unless it were a strain I really wanted (the seeds will all be female.....and want to hermie themselves.)

DONT put her back with the others and see if you can track down the original reason for the hermi-ing (?) so you can be sure your other plants dont do it as well.