She isn't going to miss it at all. Not at all. You made the right decision. Cornsnakes have not very great sight anyway. She could have gone through weeks of treatment for this eventual end, anyway. Now it will just heal up and she'll be perfectly fine.
I have a foster dog. He had "cherry eye," where the third eyelid gets stuck across. Vets do a surgery to tack it back. He was a stray, so I don't know how long it was like that. So he went in for a neuter, and to get his eye fixed. It had looked so terrible. All I could imagine all day was picking him up and seeing his big golden eye, finally free from the misplaced eyelid. Instead, the eye was removed, because when they went to fix it, the eyeball was dead. I was NOT prepared for that, and I felt such a sense of loss. But the dog- after the stupid thing was healed (there was lots of swelling, itching) he never cared. He hadn't seen from that eye for who knows how long anyway, and it was a relief to have it gone. I mostly forget he doesn't have it, actually.