Hi Asi! Welcome to the forum. I'm glad that you're wanting to do this the healthy way. I have seen those proana sites, and that stuff is terrible for you. You would lose weight, but your metabolism would go down so low, that as soon as you started eating a normal amount, you'd gain back even more weight.
I'm 23, and I weighed about the same as you when I was 18. Get into the habit of a healthy lifestyle now, and the weight will slowly come off... but it'll actually STAY off too! Good luck!