If you have ever picked kids up from school (or been picked up), then you can understand the key concept behind Node.js: asynchronous i/o.
Have you ever learned a C-based language or Java? Before web development took off in the mid-2000s, those languages were the most popular. And they are still used by hundreds of thousands of companies today.
"This visual explanation will help you understand the basic mechanics behind Node.js. Learn why callbacks are necessary, and the difference between blocking and non-blocking...."