What an interesting question! One of the fascinating things about stars is that they can come in so many different sizes, they are not all the same size. Most stars are much larger than Earth. In fact, the sun is classified as a star, and it is one million times larger than Earth! The reason that stars look so little is because they are very far away from Earth. The sun is the closest star to us and it is 93 million miles away. The next closest star is over 4 light years away! Now for your last question, why do stars look like they are twinkling? This is because the light has to travel so far to finally reach us that it sometimes doesn't follow a direct straight line, especially in earth's atmosphere. So we see this small movement of the light path as blinking or twinkling. I hope you enjoyed this answer and continue to learn more about stars!