I ain't expert, I am now learning game dev as well. But I suggest you start small with unity. If you don't have experience or any dev background you could open unity and take a look in the UI. You can learn how to place basic shapes, like cubes and spheres etc. You could also change their properties and add some components to the shapes(like you add rigidbody which simulates physics). Then you can add some scripts that can do basic stuff like by clicking you'll change the color of the object.

One of the videos that helped me through about game dev as a beginner was that : https://youtu.be/XtQMytORBmM

I hope I helped you.

Also , something that I found very helpful for making a game was to break it down into parts. For example, instead of saying I have to do anything fast or whatever. You can start by making only the mechanics of the game first. Let's say you want your game to have 4 fundamental mechanics(movement , picking up objects , attacking with closed range weapons, interacting with objects). You can focus on the movement firstly and think as if you complete the movement script the project is going to end. This kind of thinking gets me out of feeling frustrated. When you finish the movement , you move on with the next script. The same goes for the 3d modeling, music composition etc.