I think my tastes have improved. For the most part, I still listen/enjoy everything I did in past years of my life.
Age 6/7 -- Bruce Springsteen.. my first experience of "real" music. Born to Run was my album of choice.
Age 9 -- Aerosmith, Cream, and Guns N' Roses.. odd combination, I know, but I really was into these three guys in particular
Age 11 -- Aerosmith, Guns N' Roses, Cream, Black Sabbath/Ozzy Osbourne.. again, not quite sure about this one.. maybe I thought I was cool becuase I was listening to hard rock
Age 12 -- Nirvana, Aerosmith, Black Sabbath.. I got into the "grunge" thing at about 12/13 and quickly found it "lame".
Age 14 -- Eric Clapton, Pink Floyd, Neil Young, Heart, Jethro Tull, Phish, Gong, Radiohead, Disco Biscuits
Age 16 -- ELP, Frank Zappa, Phish, Steve Kimock, Santana, The Beatles, Yes, ELO, The Rolling Stones, Bob Dylan, Fleetwood Mac, Talking Heads, Genesis
Age 19 (Current) -- Rush, Miles Davis, Neil Young (again), Lou Reed, John Coltrane, The Mahavishnu Orchestra and John McLaughlin, Tony Williams, Billy Cobham, Beethoven, Bach, Handel, Jeff Beck, Herbie Hancock, Jethro Tull (my favorite classic rock band ever), Cannonball Adderly
Particularly between the 14-19 age groups, my listening habits only expanded, and didn't really change. I am still a huge fan of the jam bands, for example, and go to their shows regularly. And, of course, my listening was certainly not limited to these bands nor these styles of music. I have a large music collection, and my above list only contains the absolute best and favorites of all the "classics" that I have listened to over the years. I could list thousands of artists of whom I own records from, and still enjoy today, but that'd take forever
I feel my tastes have not just matured but have also opened up. When before I was only listening to classic rock, I am now listening to a lot more contemporary works and a lot of the more "sophisticated" works such as the 50s-70s jazz recordings, and the better-known renditions of classical works from composers like Bach and Beethoven. I also have a soft spot for Phillip Glass.
I think that it is important to enjoy some music that strikes the heart, and others that strike the mind. The mixture is the key. Neil Young and The Mahvishnu Orchestra belong on the same list together, even though they play completely different styles of music and accomplish two completely different goals.