When things didn´t go according to plan. MIT essay.

Please I need help with this prompt! Tell me what do you think about the content!
Any editing of grammar, spelling, structure will be welcome!
Thank you in advance for your time! :)
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Tell us about the most significant challenge you've faced or something important that didn't go according to plan. How did you manage the situation?(*) (200-250 words)

My first camp in the community help association "A roof for my country". The beneficiaries usually are extremely poor, living in the country side. We had three days to build a house and then went back to the city.

This project pretends not only build houses, but also provide the families a bit of happiness by sharing a good time with the volunteer builders. That was not difficult, this people is very friendly and obliging; they preferred for us to be comfortable at the table while they were eating on the floor. I learned to appreciate them a lot to the point of calling them "my family".

On the second day, my group had built the foundation of the house. However, when the leader came to supervise, we had a terrible disappointment: a minor mistake in measurements. That meant almost everything had to be rebuilt! Our task now was finishing the house in half the time it was supposed to. Big challenge! We could not destroy that family's hope for safe shelter. From there on, we multiplied our efforts. Even I did some duties meant to be done by men, but I didn't care.I would do whatever it takes to finish the house on time.

We were supposed to leave the community at 5:00pm, we finished the house exactly at 4:50pm.
Sleeplessness and fatigue were overshadowed by the happyness they showed while hugging us. I saw tears of joy streamed down the face of Lorena, the seven-year-old daugther.

That was priceless!

Thank you so much! That was extemely helpful! :)
Grammar is not one of my strenghts!
I will correct it!

I would like you to criticize the content too! Please!
Do you think it is weak?

Regarding the first sentence, what do you think about: It was my first camp in the community help association "A roof for my country"? Is it useful?

No problem :]

I just think as one word of advice, since it is a formal essay, try not to include contractions like "didn't" and "I'm". Instead, it's better to use full words.

I think your new first sentence sounds great, especially since it is a full sentence that can easily start off your story. Just make sure the rest of the essay is in the form of a story going in chronological order.

If you put "It was...", then the next sentence should be something like "the beneficiaries I was working with were usually extremely poor". In other words, its best if you keep it all in Past Tense-- that way, it flows.

And I don't think it is weak, because it definitely sounds very important to you.

The only thing is, maybe you could spend less time explaining what the project was about and what you did there so you can focus more on the challenge. Elaborate on why it was such a big challenge. Did you feel like giving up? Did you have to encourage others so you could all make it through? Did facing this challenge change you in any way?

Those are just questions that could help you tell your readers a little bit more about the challenges you faced.
With that, I think you'll be set :}