If...

If we are not timid and full of confidence, maintain a good attitude and strong energy, and work hard, we will realise that "shining is not only something the sun can do, we can also shine."

You could say "you can also shine", but then this should agree with the pronoun in the rest of the phrase, so you should change the phrase to "If you are not timid and full of confidence etc etc"

Good job :)