I remember I was 18, at college, and was eating in the dining hall with my friends one evening. We somehow started talking about our favorite colors and I said my favorite color was yellow probably because my name looks so yellow. They stopped eating and stared at me like I was crazy. They asked how does your name look yellow? I was like, what do you mean, it just is yellow. Do words not have colors for you? And just saying that out loud I realized how bizarre that sounded and that I didn't have an explanation for it. I honestly had never thought that much about the fact that words had colors for me. They proceeded to ask me what colors a ton of words were and then tested me again a few days later to see if I said the same things because they didn't believe me.
And that's how I found out I had synaesthesia.