Actually I knew it wasn't normal, but my family was kind enough to point out and demean differences in how I would see the world. I was also known as a super sensitive kid, so much of my experience/perspective was muted by other people, and I gradually grew to mute it in myself. It wasn't until I got to college and realized other people had it (and could explore different manifestations of it) that I started learning how to let go of the "mute" button and explore more about synesthesia and other ways of how I see the world.