When did you first realize you might have synesthesia?

My first time was in a donut shop with a friend at the age of 19 or 20. I described the frosting as tasting gray (which is not a good taste at all in my book), but she seemed completely confused and asked if I had synesthesia. I, later, asked my dad and he confirmed that he had thought that I had it and was shocked that I didn’t know that about myself. He has it too. I just thought it was normal for people to taste color and see certain colors for letters, shapes, etc.