This was just a random shower thought: Drinking age in Indiana is the younger of 21 OR whenever you obtain enough college credits to be considered a senior in an Indiana university. It will encourage local kids to work harder academically and out-of-state kids to come to Indiana. Not that kids aren’t drinking underage anyway, but this will help them avoid the hassle of fake IDs, criminal prosecution, being turned away from bars, etc.
No, this is not a particularly serious idea. I just know of some studious kids who, with AP credits and so forth, had senior level college credits by the end of their freshman year.