I apologise. I didn't assume your age or mean to be judgemental. But generating a test render, to make sure the program works for you should be something to do early in the process. What if it couldn't render on your system for some reason, but you didn't find out until the end. And you had to start again with a different software. That would be quite dire. So it's not about drafts, so much, as it is running it once, to check that everything's setup and works for you. So it sounded like a new person's mistake. Something that I do see a lot from younger or less experienced animators. As a professional, I'd hope you'd see this. It's a lesson that I keep re-learning by rushing with things.
Setting up ffmpeg is pretty straight forward once you've done it a couple of times, but is fiddly at first, so it might just be a case of setting the wrong path. If so, you might be on your way.
If not, then rendering to png would be better than jpeg. It gives you a transparent background, if that's what you need, and a clearer image. Then using a video editor to assemble those images into a gif.