This might not be feasible. If you are making a game for yourself and your kid, you might not be using assets (art, sound, etc.) that you could distribute/sell in your game.

I made a game for my daughters 3rd birthday, recorded some Blipi and Coco Melon songs off youtube that I put in the game. I would not have the right to sell the game without securing rights to the songs (unless I want a lawsuit on my hands).