Like Jeremy, i never did albums either but i did do songs!
For a legal adult here (18, so in 2012) it probably would have been a mix of things! that was the year i went to college so it was a mix of my real tastes, some indie kid music, and normal club music but stuff like Hurts, Red, Red Jumpsuit Apparatus, and Imagine Dragons then 'those' songs like Call Me Maybe, We Are Young, Die Young, Somebody That I Used to Know, Gangnam Style and Drive By... and then random things like 'before he cheats' and radiohead! oh and Birdy - Skinny Love
As for 21, well at the moment, im listening to Bastille, Imagine Dragons, Lana Del Rey, Fall Out Boy, Sam Smith, Red Jumpsuit, OneRepublic, Hurts, Raleigh Ritchie, Arctic Monkeys, Florence and the Machine, etc..
my music tastes are all over the place