I have no idea how someone is supposed to know their testosterone level, without a blood test. Saying you are kind of a nerdy person, isn't really a sufficient test for testosterone levels. I could say I have a large penis and grow a beard quickly, but really that isn't a valid test either.

I don't think being a meat head is really an accurate test for levels of testosterone either. Though if they are super aggressive that could be a sign of having way to much(and possibly a result of steroid abuse).