DD13 learned to read at 4. She had a friend who as families we were really close. When the friend and her mother came over my DD went to read to her. The friend freaked out, wanted nothing to do with DD reading to her. DD stopped reading for a while. The funny thing is that four year old friend is very dyslexic and I have wondered if the reaction was somehow related to that.
DD2.9 learned her letters and at about 20 months was really into X. She had figured out how to write it etc. We went over to a friends house who was painting. The other little girl was making scribbles and then declaring them to be things such as cats etc. My little one painted an awkward X. The other little girl asked what it was. My little one answered, "Just Painting." I could not believe at 20 odd months that she was hiding what she was doing.....