Need to Improve Japanese Speaking!

A few days ago, I was asked by the teacher incharge to evaluate the worksheets from WAO company. While I was writing, my teacher shared something to me.
She said that next year, there will be a boy transferee from Japan who is 17 years old. The teacher was thinking of me since she thinks I know how to speak Japanese. The transferee will be staying in the school for 2 years and he must graduate.

I think what she wants to say is I should help him understand the lessons.

If it's going to be so, I have to improve my Japanese starting now! I need to speak Japanese a lot and my brain should be 1/4 Japanese. Of course, English should take 1/2 of my brain and my national language should also be 1/4 of my brain. So my goal is to learn Japanese as to how much I've learned my national languiage. I know it's going to be a challenge for me because I also have many thing to do just like studying other subjects but I know it's going to be for the betterment anyway. Learning Japanese is not a problem for me because I think I am enthusiastic to learn Japanese so just adapting the language will be a bit easy.

If I notice that my Japanese is getting improved, I'd be really happy for what I have achieved.