DD has also known colors way before 18mo and we did not teach her. Basic shapes too, except I remember showing her hexagon, octagon and rhombus at some point when she was interested. I do not use those words in my everyday language so there is no way she could have just learned them. With numbers I have no idea when she learned them, she never actively asked about them like with letters and seems that she has known them for ages. I was thinking maybe she learned them at the daycare? Same with the body parts she has known them as long as she has been able to communicate.
From her daycare they send home a short letter everyday telling us what she did that day and it usually says that she was helping her friends with puzzles and teaching them numbers LOL She is not even 2.5 yet
