I have always been very skinny, or thin and smaller than
most kids my own age when young.
But it hasn't made a big difference far as how I live my life.
I eat what I want and like not having extra weight to carry.
I don't want to get all "muscle bound" like some guys either...
In general I am fairly flexible, but I feel uncomfortable physically with a woman who weighs more than me. And at 5'9 and 125 lbs it is difficult for me to find a partner who weighs less than I do (even if they are much shorter).