I am not a fan of keeping wild caught native species. If it was an invasive species, the choices are clear: euthanize per Department of Wildlife request or keep it as a pet. That is what we did with a Cuban tree frog inside my home. Little guy grew in weight, eats well, had a missing leg so he would no longer have to worry about escaping from death again. But he will never be allowed out.
Lets say your wild caught snake did not carry any parasites or disease. In a bigger perspective, you took away his ability to do what he does best: hunt pests/rodents thus helping (no matter how little) keeping the rodent population down, contributing its genes if it survives long enough to breed to further increase survivability in its young or end up food for another predator that itself could need it to feed itself or its young. I know it sounds dramatic but if we are saying one's life matter that much in captivity, then same should be applied of its importance in the wild.
Look at this way too: there are thousands of captive bred corn snakes available. One of the driving reasons to captive breeding is so we don't have to take from the wild population.
It is hard to decide for our snakes that captivity is better.
With all that said, the choice is yours. I won't judge you for it as long as you are taking good care of it. I just want to think it through before you get more attached to it. That snake is kind of cute so I would have been tempted to do the same lol.