Keep in mind the differences between areas of the country. Generally speaking BG and LMB live longer and grow slower up north vs TX. It can take several years longer for a BG to reach max size in colder climates. In your location a 6 inch female BG is good. Until you can determine how to manage your situation I would not remove any large BG but would harvest small males and some females. In more northern areas , due to spawning dynamics of BG, it is often suggest that you not harvest the largest male BG.