How to get my back ribs to show?

Okay first NO RUDE COMMENTS. Okay, well first off I am 15 and I weigh 106 and I am 5'6. My pelvic bones show and my top ribs show a little. i have been through alot with weight and I just want to be like super scrawny. Please dont say that unattractive bla bla I just want answers. I want to look scrawny in a bathing suit and not curvy so how to I get the back ribs on my back to show and get scrawny. I eat very little but it's not helping.