I remember when A and B were commonly used drive letters. C was a luxury. D was outright bourgeois.
But for some reason, drive letters starting with C feel completely natural, too. Maybe it's because C is also the first note in the most widely known musical scale. We can totally afford to waste two drive letters at the start, right?
D was typically a CD-ROM drive. So when CD-ROMs went the way of the dinosaurs, where did D go ? Is it always some kind of SYS drive nowadays ?
Oh bless you and your youngsterness. A and B, by convention, were reserved for floppy drives and C was typically the first hard drive.