Born of 28 wks, twig thin 29 male, 99lbs, 5'6" asthmatic, look like 19, diff socializing, girls cnsdr me a kid, earn no respect due to child like body?

Exercise. Consider regular exercise including strength training to bulk up your muscle. Your problem with socializing is likely partly from your posture and attitude. Be more self-confident and you will likely become more attractive to the other sex.