Is the title a necessary ? I guess it gives people a flavour of what your message will be about.. Think of it as a general "subject" label.

So let me introduce myself.
My name is Kelly. I'm 15 years old. I'm French Caribbean (West Indies), or more precisely, Martinique. I'm so proud of my island, even if we are not the biggest or one the famous islands or the most known in the world, I don't know, I love it. I always ask myself if, as little as we are, does are there people who are interested in us too.* I'd like to know if we are envied by anyone**. Are there people who want to come to Martinique like they want to go to Hawaii or ...? 
I lost myself in my presentation .. I'll finish later..

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*Comme "intéressé par qqchose"

**En fait, c'est une expression un petit peu bizarre en Anglais...

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Hi Kelly!

Je viens aussi des Caraïbes (des Bahamas!). D'éxpérience, car tu vis aux Caraïbes, il y aurai toujours des gens qui sont intéressés par ta vie et ton pays. Soit fière! Et moi, aux Bahamas, je savais de Martinique--nos cousins français. Malheureusement, je n'y avais jamais été.

Peut-être, tu dois écrire beaucoup de Martinique. ;)

You're doing really well at fifteen. :)

Is the title a necessary ? Yes it's neccessary, it lets the reader know what the topic of the note is. If there is a title people are able to decide if they want to read the note.

So let me introduce myself,
My name is Kelly, I'm 15 years old. I'm French Caribean (West Indies) most exactly specifically from Martinique. I'm so proud of my island, even if we are not the biggest or one the famous island; the most knowing well known in the world, I don't know, I love it. I always ask myself if as little as we are, does are there are people who interest themselves too are interested in us. I'd like to know if we are an Envy's interesting subject. Are there people who want to come in Martinique like they want to come in Hawaii or ...
I lost myself in my presentation .. I'll finish later..