Making a game is a daunting task. Some people are original. Someone like Halliday from Ready Player One. They have a vision about the original concept and energy to go all out to make it happen. Rest of us copycats, there are many decisions to be made. Especially if you want your game to stand out in millions of games and apps already present in the app store.
If you have to make an indie 3D game, that means just one person doing it all by self. Creating 3D models, rigging those, developing textures and creating realistic 3D worlds can take hours and hours. Bringing that to the level of commercial games needs special skills. Unless you have abundant time on your hand and you are super gifted, I will not recommend going through this route.
Making 2D games is relatively less complicated, but you will hate it if you are not a good artist. Taking one dimension out of a game takes away lots of fun but also takes away many things that a game developer has to build. Game development platforms like Unity offer physics and lighting engines in 2D which makes 2D games realistic as 3D games. But if you have fun concepts for games and want to try those out quickly 2D games should be the first option for indie game developers.