Для тех кто знает грамматику английского языка. Проверьте правильность сочинения.

It happened a few years ago. I was 13 years old. I was in the 7th grade of high school. Once a week I attended additional drawing lessons. Once I went to the lesson. Suddenly I saw 1000 rubles on the road. I picked them up and took them. On this day I was very pleased. It was the best day of my life.
Писал с переводчика, поэтому могут быть ошибки, проверьте, пожалуйста. Спасибо!)

It happened a few years ago. I was 13 years old. I was in the (seventh) grade of high school. Once a week I attended additional drawing lessons. Once I went to the lesson. Suddenly I saw (One Thousand) rubles on the road. I picked them up and took them. On this day I was very pleased. It was the best day of my life.