Its great that you are not attempting to make GTA for your first game😃, so i think you are on the right track. What game engine are you using? looks like you are set to complete the game to me.... Just keep it small, just do the one level so you have something to submit to the jam.
The Game Jam has ended....I did not submitted the game, it was too late....Right now I want to finnish what I have started. I literally deleted the game files start all over again. I started everything was great then, due to some error now i had delete again make a new game...Right now I dont know what to do? I am stuck , like making a first game is like climbing a mount Everest without any safety measures...To answer your question i am using godot cause am beginner game developer, even tho never completed building my first game....Also thanks for reaching out
Some you tube vids to get you going:
Start with this
And this is an amazing website to help:Then hit some of these you tube vids
https://www.youtube.com/@queblegamedevelopment4143