You are allowed to donate your money where you see fit. On the other hand, is your old HS still run by the same administration? I prefer to tithe and put money directly in the hands of those who will benefit, so maybe instead of the HS you could find a needy family with a child who attends and take care of a few basics for the kid; Shoes, maybe a couple months of lunches, that kind of thing. Someone gets the benefit, you’ve made a contribution and you know that it has helped someone.