A BB and a 1.5 yr old may relocate elsewhere. You may never see them again. Not until 2.5 yrs plus do bucks usually choose a core area.

I don't shoot them on purpose, but have killed a few. Killed one this year after passing him up at least three times. He bedded close and allowed me to climb down walk over and take the shot. At that rate, I figure no loss on a deer that doesn't fear or know about human.

No need to beat yourself up for shooting a button buck IMO. I would feel waaaaaay worse shooting a 2.5 year old 135" 10 point.