My mom says I'm TOO skinny...?

OK see I'm 5'4/5'5 and around 115 pounds which I ume is normal but my mom says I'm too skinny. She often buys me clothes that are about 2 sizes too big. I was chubby around 13 when I was going through puberty but around 14 I lost my 'puppy fat'. My mom complains my shoulderblades and my arms are too skinny. I eat TONS of junk food (like 3 times a week even though I promise to eat healtily I do manage to eat healthy food inbetween.) I eat around 1,200 to 1,700 cal a day. My neck is distracting though (my neck is very skinny and the bones stick out alittle this is the same with my pelvic and collarbones and my wristbone and my hands are bony and veiny my elbows are sharp also) I'm small framed and I have small shoulders and my waist is 23 in (my hips are wide though) and my bodyfat is around 10 to 15%. I have diposits of fat on my stomach and my upper legs (but my stomach is pretty much flat) I'm not anorexic but I often think the other girls in my cl are fat or chubby because they look like they have more fat on them even celebrities appear wider than me. Some boy called me twig arms. Is it normal for me to be this thin even at a healthy weight? I'm 17