Einstein was a famous scientist who changed the world, and made math and science exciting. What he says means don't be afraid to make mistakes. Don't be shy about trying something new. Go ahead and try, no matter what.
Dr. Dyer says you have two choices: cry OR get up and be sunny, no matter what kind of day. You have to choose. Sometimes I feel bad and I don't want to do things. But I can also get up and do my best. It is my choice to make.
Haha! There are a lot of silly people and silly things in the world. Trying new things, exploring strange places, and doing something for the first time makes life interesting!
Go back to school and do your best. Talk with your friends and your teachers, ask lots of questions, and do your homework. And have fun, this is very important.