Ask HN: Have you rejected an offer to work on a project because of self-doubt?

Hi, I'm a third year CS student. I have been coding for a little over two years. I have worked on a few side projects. Recently,more than once I was approached by people who wanted me to help implement their projects. But I have always refused just because I think I'm not good enough.

So, I wanted to ask the HN community: have you ever done that? how do you deal with self-doubt? Thank you!