Nhờ sửa bài giúp

I would like to say that it was the first time that I did something like that.

I painted a mural in a secondary school.

Honestly I didn't expect that the teacher and the principal from the school asked me to paint a mural so I was nervous and exited because I only had painted drawings in a wall of my room and I had never painted in pulic but I think It was a fantastic experience in my life!