Okay kiddo, so imagine for a moment that you're playing a game and you've already decided what kind of character you want to be. Maybe you want to be a superhero who can fly and has super strength. Even before you start playing the game, you already know who your character is and what they can do.
That's kind of like what some people believe about Jesus. They believe that he existed even before he was born as a baby in Bethlehem over 2,000 years ago. They believe that he was with God, who created everything, and that together they had always existed.
This idea is called the "pre-existence of Christ". It means that Jesus wasn't just a regular person who became important because of the things he did, but that he was always important because of who he was.
Now, not everyone believes this. Different people have different beliefs about who Jesus was and what he did. But for those who do believe in the pre-existence of Christ, it's a way of understanding his special connection to God and why he was able to do miracles and teach people in such a powerful way.