Hi! This is my first jam ever! I don't know which engine to use. I have 3 engines: scratch, unity, and godot. I'm been using scratch for quite some time - this is my profile: https://scratch.mit.edu/users/CometBlazer/. I barely know anything about unity (I don't even know how to use unity hub ☹  )and I just started to learn Godot by following tutorials online. Which engine should I use?

the one you have the most fun  using

Use Scratch if you’re the most comfortable with that, with enough skill you can make some amazing games in scratch

If you want to make simple 2d games, pick unity or godot. If you want to make a 3d game, pick unity (or godot if you know it better)