Hello! You can write, "I don't have confidence". Confident is an adjective. For example, you can say, "I am confident that I will pass my test." Confidence is a noun. I have confidence that you will learn English if you practice speaking every day. Be Confident. Don't be afraid to make mistakes. I am proud of you for learning English. I am teaching on italki. Feel free to look at my teacher profile. I would be happy to help you.

As you learn and speak more English, you will get more confident. Keep trying!