At what karma level do people stop judging your account?

I’ve had my account for 6 years, but I’ve spent that entire time just reading and never interacting. Now that I’m finally trying to participate, I’ve realized my "karma to account age" ratio looks a bit suspicious!

I feel like when I comment in bigger subreddits, people see a 6 year-old account with almost no karma and assume I'm a "sleeper bot" or a bought account.

My question is: At what point/karma level do people stop judging your credibility based on your score?

Thanks