You're welcome!
I would say that its probably better to concentrate on western holidays, but make sure you briefly cover Korean holidays as the kids really love explaining them to you, just make it look like you don't know much about it. They feel proud knowing they are educating you.
If you do do the Korean new year, it would be a really good idea to also talk about the Chinese new year and make a comparison. I'm currently doing this with my class and they are loving how strange and exotic the Chinese celebrations are to them. I will post my powerpoint for this when I am finished with that topic.