When you can jump a full course 5cm above the height you will be competing. Then it will be a piece of cake, jumps will look smaller and your horse will have more confidence in you. And make sure you have fun, that’s the important part many people forget
I think it's when you feel that you have enough trust in your horse and in your capacity to deal with your nerves to finish a course calmly 🙂
If you have the right trainer, a great preparation and the right horse there's no reason why you couldn't do it!