They were kept secret. Jeremy needed to be kept a secret. He couldn't get himself killed when the Mikaelsons found out about him. But he knew he had to tell someone. Especially when he have a baby to protect. So what happens when Jeremy finally wants to tell his sister? Jeremy loves his sister. Truly he does. But she cannot NOT be biased. No matter how hard She tries. That's what he fears but if it comes down to it, he will leave. Even if he has no sister.