Why Are Some Stars So Big?

Imagine stars like babies, some are born big and strong, while others start off small. A star's size depends on how much stuff it was made of and how fast it uses that stuff up. If a star is born with lots of material around it, it becomes a giant star. If not, it stays small. Think of it like eating: if you eat a lot, you grow big; if you don’t, you stay tiny.