Motivation letter ?

hey guys! I am applying for a Bachelor in Economics/business.
I need to write a letter with 400 words MAX, answering the following questions :

Why did you choose to study this specific programme? Why did you choose to study abroad? Why did you choose to study at the University of Amsterdam? Do you have any ideas about your future career path?

We are looking for students with excellent quantitative (mathematical and statistical) skills. You are suited for this programme if you would like to bring an international dimension into your life and have the ambition to pursue an international career.

I've written a 562 words letter!
I need help reducing it, I also need a hand concerning grammar.
Do you think the arguments in this letter are enough to be accepted ?
Thank you very very much guys!

__________________________________________________________________

Dear Sir or Madam

I appreciate this opportunity to provide further background information in support of my application for entrance to the Economics & Business Administration at the UvA for the 2015 intake.

My name is x. I am x years old.
I was born in France, but at a young age, my family and me moved to Mexico.

In the past year, I gain a strong interest in economics, business, finance, and mathematics applied in economics.
I graduated from a French High School in Mexico City in scientific series (minor in Physics). This specific series has a higher level of mathematics and physics, and is intended for people wanting to pursue an Engineering Degree.
Surprisingly, I gain strong interests in Economics and Business when I took a gap year in Los Angeles, CA, in order to master my English skills (I also received a Sound Design certificate).
My dad is an engineer and businessman in a Mexican based oil company, and while in my gap year, he explained to me how to apply economic analysis to the evaluation of engineering challenges in the petroleum industry. He showed me real-world examples and case studies demonstrating the economic performance in organizations, and I found it was really interesting, to the point where I decided to make it my future career: I would like to prepare myself by going through your program, and eventually do a Master’s degree in Business Economics (Organization Economics path).
After doing so, I would like to come back and work in the petroleum industry. Mexico’s new law regarding oil industry will require professionals with an international career, knowing how to handle multicultural business relations will be needed. Although, a lot can happen in 4 years, nothing is certain.

Studying abroad has always been a part of my life.
Since I was a child, my family has been always moving to new cities due to my dad’s work.
Studying abroad has helped me to adapt quickly to situations, but also understand cultures and people in order to interact with them in the best way possible.
I spent one semester in InHolland University in Haarlem.
I realize that this university wasn’t for me, I didn’t feel like I was progressing the way I should, and it did not feel like a challenge. A lot of international students in the last year were having a lot of troubles with the university and cannot graduate.
I was demotivated very fast. On top of that, I had some family issues to attend.
I decided to come back to home country, and apply to the UvA.
Dutch culture is very welcoming, I truly enjoyed a lot my stay in Holland, and I wish to come back as soon as possible.
The UvA has a strong international program, which I really like. Moreover, it is one of the best universities in Europe.
The reason why I feel like I can be a part of the UvA is due to the fact that I think of studying there as a challenge, where I can prove myself that through hard work and motivation, great things can be achieved. Moreover, I would like to be part of the strong international students community, where I can contribute in a very good way.

I hope this letter will be given your full consideration and I will be happy to provide any further information you may require.

Yours Sincerely,

X