In this world, one thing is real, and that is money.

If you have money, then you can get anything that you want, otherwise you are a loser in this world.

If you are belong fromto a rich family, then your life will shorted,be easy. But if you are from a middle class background, then you will have to face many difficulties.

It's always "belong to."
I'm not sure what you meant by "shorted" here. From the end of your sentence, I assume you meant that life will be easier if you are rich.

You cawon't be able to follow your dreams due to lack of money ,. Due to the lower financial condisituation of your family, you will want to change this ,. To change your financial condisituation, you need money, so you have to leaveabandon your dreams and start earning money .

We were just in future tense, so keep the future tense here too. Typically we say "follow our dreams," in the plural sense. This way it's generalized /dreams/, whereas "dream" singular begs the question of what, specifically, the one dream is.
You could also say "leave your dreams behind"

All these things that I had said in this paragraph in've written in this text are from the perspective of the oldest child of the family.

A bit easier to read: All that I've written here is from the perspective of the oldest child of the family.