My lLife

My first name is Solen and I'm fifteen years old.

A native speaker wouldn't say "first name"

Next year, I will be in Première (this is the fFrench scholarity) and I tookchose the options of Mmathematics, Pphysics and Nnumeriques and Science of informatic.

I love tod studying sciences at school and I'm very good in Mat mathematics.

Outside of school, I practise Hhave played handball since I was five years old and I play a little bit of guitar.

I love the eEnglish language and I want to learn it because it's thea common international language.

My lLife

My first name is Solen and I'm fifteen years old.

Next year, I will be in Première (this is the french scholarity) and I took the options of11th grade) and I chose to study Mathematics, Physics and Numeriques and Science of informatic.

I searched on the internet and knew that première means the year before the last year. So you could say 11th grade.

I love to study sciences at school, and I'm very good inat Mathematics.

You could say math for short, but mathematics is also correct.

Outside of school, I practisece Handball since I was five years old and. Also, I play a little bit of guitar.

I love the eEnglish language, and I want to learn it because it's the internationa universal language.

English language is not wrong. However, English sounds more natural.

My first name is Solen and I'm fifteen years old.

When introducing yourself, you can just say “my name is…”

Next year, I will be in Première (this is thea french schoolarity) and I took the options ofselected Mathematics, Physics and Numeriques and Science of informatic.

Not sure what you meant by “scholarity” so I guessed what you were trying to say.

I love to study the sciences at school and I'm very good in Mathematics.

Outside of school, I practisehave played Handball since I was five years old and I play a little bit of guitar.

Next year, I will be in Première (this is the french scholaritysecond last year of high school) and I took the options of Mathematics, Physics and (Numeriques and Science of informatic?).

scholarity is an archaic word (I had to google it and it seems to mean approximately, "educatedness"). I looked up a French-English dictionary and it seems the meaning of Première you want is the "penultimate year of high school". Americans would call this "Junior year", but note other English speakers (e.g. British, Australians, Irish, etc.) don't name their school years, so if you're talking to someone who's not an American, don't expect them to have a clear idea of what the named years are.

> Numeriques and Science of informatic

This is only half translated. Some googling seems to indicate this is what we'd call "computer science" in English, but I'm not confident enough to say for sure.

I love to study sciences at school and I'm very good in Matheat matichs.

More natural to shorten "mathematics". Americans would shorten it to "math", other English speakers would shorten it to "maths".

Outside of school, I have practise Hced handball since I was five years old and I play a little bit of guitar.

Names of sports are not proper nouns so are not capitalised.

I love the eEnglish language and I want to learn it because it's the international language.

Names of languages and nationalities are proper nouns so are capitalised.