I had a meeting with the person who's going to get married this weekend.

-> I had a meeting with the person who's getting married this weekend. 

In korea, we have a conventional event with friends before wedding. Usually he invites friends to the restaurant and buys foods for them in a restaurant. 

-> In Korea, we have a conventional event with friends before wedding. Usually, he invites friends to treat them in a restaurant. 

And then all persons who are invited celebrate the future bridegroom for the wedding. It was customary event often happened to the new bridegroom and bride.

-> And then, all persons who are invited to celebrate the future bridegroom for the wedding. It was customary event often happened to the new bridegroom and bride. 

I also did that before my wedding. When I went to the restaurant, many people already got together to have dinner. I also had a great meal with them.

-> I also did that before my wedding. When I went to the restaurant, many people are already there to have dinner. I also had a great meal with them. 

I came back to my home because I felt a little bit tired. I didn't realize there was a soccer game until I came home. It was the match between Costs Rica and our country.

-> Good sentence.

It already started and I could watch the game from the middle of the second half. We korean team was losing at that time by 1 to 2. I watched the game while looking forward to our victory.

-> It already started and I could watch the game from the middle of the second half. Korean team was losing at that time by 1 to 2. I watched the game while looking forward to our victory. 

But after a while we also lost the point. So the score was changed by 1 to 3.The match ended up the Cost Rica's victory. Korea team seems to have to practice more and more.

-> But eventually, we lost the point. So the score was changed by 1 to 3.The match ended up the Cost Rica's victory. Korea team seems to have to practice more and more.

[C O M M E N T]

Good day Rome!

I admire your effort to write in your diary and to share your experiences towards the event. I just want you to focus in your proper noun such as korea to Korea. Proper noun always starts in a capital letter. And also take note of the prepositions that I change. Until then. :)

Teacher Illah ~