ПИСЬМО My friend told me that he wants to be a pet. I was surprised at his decision he...

ПИСЬМО
My friend told me that he wants to be a pet. I was surprised at his decision he was always been afraid of dogs and he has never had any pets at home its probably because he has read book about a vets clinic
what job would you like to do when you are older?Why have you made this career choice?What school subjects do you find the most useful for your education?(100-120 слов)

Dear friend,
Thank you for your letter. In fact my dream is to become a doctor one day. I like to help people and make them happy, because I become happy too. The most interesting doing for me is studying humans, animals, and all the nature around me, so I'm very interested in biology and chemistry. Also they are very useful for my education.
I need to prepare for my test now so I need to end my letter.
Hope you'll answer me soon, 
Best wishes to you

(честно, слова не считала, но надеюсь, что помогла)