Why do our tastes grow "older" and more "refined" with age?

When I was young, I only liked things like milk chocolate and strawberry ice cream. I despised things like dark chocolate [too bitter] and pistachio ice cream [disgusting].

Now that I’ve aged some [close to 30], I find milk chocolate to be disgustingly sweet, as well as fruity ice creams. I love dark chocolate because it seems to be the perfect flavor, and pistachio ice cream is heaven!

I have found that several of my friends also went through this change; what’s the science behind this change? Have you experienced this?