You do not have to be a master to mentor. You do not have to be the best at what you do, neither you need to be an expert in what you do. You might have a passion, but that is just a like most of the time. You might feel competent and knowledgeable, but if you are completely honest that’s probably not how you feel in most cases.
If you believe any of the above is necessary to mentor, you are telling yourself a false story, you are giving up to resistance, you are pushing back something you would genuinely benefit from.
And when that is the case, you can start mentoring now. You will get back everything you put in. And more.