SarahRosos:oh sorry to hear that - but you're only 18 so you'll be fine - wish I had trained to be an instructor but at 36 it's a bit late and a big regret - when you're completely better - go for it!
Off subject but, I started instructing at 38 (anything that is!). If you have the desire, don't let a number stop you!
On subject, let it rest as long as they tell you to. Coming back early only (usually) means reinjury!