Need to gain weight!! Help?

I'm a 16 year old girl, and I weight about 103 & I'm 5'4. My legs are like sticks and my arms are thin. I hate being this skinny, but I can't help it because I have a really fast metabolism. My goal this summer is to gain weight around my legs and arms(not muscle) so that next school year I'll look less skinny. Please don't tell me to 'love my body'. So many girls diet to loose weight, why is it bad for me to want to gain weight? I feel like being this skinny gets in the way of so many things in my life(can't get a job cause I look to young, no dating, wearing shorts, looking awkward in general) I don't want to eat unhealthy(junkfood) so are there any quick healthy ways to gain weight? Thanks!!