When you're a little kid, you just like music that makes you happy and is fun. As you get older, you reach college or your 20s and you decide that music should be challenging and all art should be smart. So you start to think it makes you like high art more to put down things you consider low art. I don't even think things are low art.

This quote is saying that when we are young, we tend to like music that is fun and happy. As we get older, we think that art should be more challenging or have more to it than just being enjoyable. We sometimes start to think that high art is better than what might be considered low art–but the quote is saying that there is no true distinction between low and high art. Everything can be considered art and should be valued for its artistic merit, regardless of its perceived complexity or depth.