When you and your horse are ready. That means getting good results on your current class, training on harder stuff at home and being comfortable with it... etc.
Also, when your coach or trainer feels that you are ready-in addition to the points made by their others 😊
You should be confident with the height you’re doing right now. Going clear + placing. When you practice at home jump higher so it’s ‘easier’ when you do the completion. Hope this helps!
When you a regularly being placed at your current level with double clear consistently, and you are happy with the work you are doing :)
You know you are ready when you have gotten clear and feel confident with the current level. Also, you want to be able to jump 3 inches higher at home than you are competing so you are more prepared. So for example if you compete at 3’6 you want to practice courses at home at 3’9. Hope this helps 😊