I'm skinny what do I do or should I just leave it?

You are naturally slim, you should not try to change this. What some others say means nothing, you are the "healthy one" and think of it this way you, will probably live alot longer than they. You were born to be a model, you should focus only on that, DO not ruin what God has gave u, Use it and be proud of it. If you want to be truly be a model then U have to stay the way you are. The female modeling industry is very strict u must be at least 5,8" tall or taller, for runway. Your body weight and proportions need to flatter your height. GOOD LUCK :)