Is it ok that I am letting my 3 yr old drink coffee?

My 3 yr old daughter, Lyndsey, absolutely LOVES coffee. About a few months ago she asked if she can try some of my coffee. I thought that she would not like it so I let her try a sip and she LOVED it. So almost every morning she asks for a cup of coffee. I serve her coffee in a coffee cup that's about 2 times smaller than a regular coffee cup. It's not everyday that I let her nor is it everyday that she asks, but I do let her drink coffee. My mom said it isn't bad that I let her drink coffee since when I was my daughter's age, my mom let me drink coffee, but my father says it's wrong and I shouldn't let her drink coffee. What do you people of Glow think?