Exactly this.
Hopefully it will always be supportive and comfortable to discuss your decision making here on COTH. But don’t air it to others, no one needs the incredibly strange random reactions. Even from people we thought we knew.
It’s hard enough without that. A few months afterwards it is much easier to say “we had to let her go last spring”.
Hope you are ready when your horse needs you to be. If it matters, none of my animals had any idea. They found peace. Good luck!