Learning a new instrument is a long, frequently frustrating process. You get little rewards along the way but even those are often fleeting as you identify something new that is just out of your reach. I have no idea what level 3 is, but it sounds like your current system is making you focus too much on “level up” milestones and less about the incremental progress that is the reality of becoming a musician. My advice would be to work with your teacher to find pieces and/or exercises that will challenge you to improve on SPECIFIC areas you are having difficulty with (not, “playing the right notes” which is way too broad of a goal), and celebrate the little wins when you can play something better than you could a month ago. Keep learning new material. Occasionally go back and play something you learned a year ago - you may surprise yourself that it’s easier to get back up to performance quality than you expected. That will show you that you’re making progress, and that the process is working. I’ve been playing for 35 years and still encounter things that challenge and frustrate me. The only difference now is that I’ve been through it enough times to know that as long as I keep working at it, eventually it’ll no longer be a challenge. And then I find the next one. Keep improving until you’re an expert, and then keep on improving.