I'm exactly the same, my parents never took any interest in family holidays (we only use to visit our home country to visit their parents), TV shows, music etc. If someone was to mention a song from the late 90's and early 2000's I wouldn't know the song at all unless it was a regular on TV.
It's quite stupid that people are begrudging you for that, nobody really cares that I don't know what something is, I didn't get into music until year 10.
Just learn to ignore them, it's the only advice I can give.