A letter of advice to Janet

Date:?
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Dear Janet!

Hi, my name is Hila and I'm 16 years old. Last week I heard you on the radio show, in which you were telling the listeners about your problem in school.
I'm writing this letter since I would like to give you my opinion about it! - you have to state in short what the problem is.

Well, it might sound a bit insulting of me but I really think that your(sp. - you are) paying too much attention to your popularity in school. On the one hand, it's true that it isn't very nice to go everyday to a place where no one likes you, but on the other hand, the important thing is your feeling(s), (Start a new sentence here)I mean, don't let a few kids get you in stress(phr.) or use you and make you feel bad in return for being your friends – these aren’t friends!
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If your friends make you lie for them and risk yourself and your grades for them, then I think that they don't deserve to be your friends. Besides, you don't have to be so concerned about what happens if you don't let them copy, in the end, they won’t make "a big deal" of it. They might just be a bit upset and it will pass.
In fact, I don't even think you should see things the way you do, if they don't want to be your friends…it's their problem! And they will come back "on feet"(phr. - this is a direct translation from Hebrew, and it doesn't work in English) when they will need(gr. - no "will" after "when") something.

In conclusion, I hope my advice will help you see things clearer, but don't forget one thing for life: trust yourself Janet and no more(ww. - no other)! You can find friends everywhere you go, but your truth…this is only yours.

Where is the greeting and the signature at the end?

Hila, this is a good letter of advice. Nevertheless, you need to correct somemostakes and rephrse some of your sentences. Pay attention to my remarks. (87)
Daphna.