Whenever someone says "why don't you - flatiron your hair? dye your hair? cut your hair shorter?" I always respond with - "Why would I do that?!? I get many more compliments and much more attention with my hair curly/grey/long. If I straightened/dyed/cut it, I would just look like everyone else". I always say it in a nice cheerful voice.
Just do what you're doing, be happy with your beautiful curly hair, and don't worry what others say.