I feel your pain, but from the other end of the scale! I am 5 feet 10 inches (female) and people have always assumed that I can cope because I am tall and I look capable.
At school I was picked on for being "large" (ie I was overweight). I am now on the skinny side, and have been for decades, but because of my height I am looked upon as competent and well able to cope, even when I am not.
The only thing that you and I can do is accept ourselves the way we are, ask for help when and if we need it, politely reject help when we don't need it, and not worry what other people think of us.