August 12ndth, 2025

"1st", "2nd" and "3rd" are the only exceptions. Everything else will use "-th".

Today, we changed seats at school.

Generally, the plural form is used here.

I felt happy, because I have never changed seats in my life.

Mind the tense. You're writing about the past, so the past tense should be used.

It was such a good experience.

(1) "Good" is a very generic term. Alternatively, you can say "fun experience".
(2) In English, we need to make clear the quantity of things through words like "a".

And, I went to MUJI in Metrotown.

Merge this sentence with the one below. I removed the period to allow for this.

Bbecause, I shouldhad to buy a new notebook.

(1) Generally, we will not start a sentence with "because", as it disrupts the flow of the writing. This is why I suggest merging this sentence with the one above.
(2) We typically also do not place a comma behind "because".

August 12ndth, 2025

Today, we changed seats at school.

I felt happy, because I'd never changed seats in my entire life.

It was such a good experience.

And, I went to MUJI in Metrotown.

The one in Burnaby?

Because, I shouldneeded to buy a new notebook.