Its funny, but I actually feel the pressure to go the other way. My DD1 is fairly bright - that's not just me being smug, But she hit all of her milestones earlyish (one exception - walking, she was 13 months when she was fully walking), She taught herself to tell the time at 2 3/4 (only to the nearest hour). She can now do it to the nearest 15 minutes, but I haven't bothered to teach her the rest... She learnt all the letters of the alphabet (she pushed for it) when she was 2 1/2, started reading simple CVC words at 3 and now at 4 3/4 (just started school three weeks ago), she has just started reading Enid Blyton books (She reads most of the page, I read the difficult words - she found reading schemes boring). ... So I hope I can justifiably say that she is on the brighter end of the spectrum!
Yet, I feel an intense pressure to point out the things that she is rubbish at in every day life. When we go to ballet, gym or swimming, I just feel I have to point out to the other mums that she is no good at these things, and keep my mouth shut about the good things she does. For example, when she learnt to tell the time, I never said a word to anyone outside the family - felt I couldn't in RL in case other people would think I was boasting.
Whereas DD2 is darned lazy (and perhaps a bit thick!) and is behind her milestones, certainly in her speaking (Actually quite a long way behind her friends). Yet, I feel that I can be open and honest and sing her praises with others, in a way I could never do in RL with DD1.