Good Job

 Grammar is good for your inner coach.  You can learn how to say 10,000 things correctly in a few minutes if you remember the rule and can make many examples.  

For producing English, relax and repeat until you remember.  Songs are good for repeating.

In this song, you matter means you are important.  It doesn't matter = It's not important.

Write about things you can do well.  What do you say when someone asks, "What are your best skills?"