Your kid is going to be exposed to all sorts of nonsense from stupid ideas to bullies and assholes, etc, unless you lock them in the house and don't let them socialize with anyone (which would be child abuse). The key is to teach your kid to not fall for bullshit and to learn how to handle different situations, even a 3 year old kid is capable of that. You can't shelter a child from all stimuli, whether physical risks, biological risks or social risks. Being aware of what risks are being encountered and how they are being dealt with is important, but full sheltering from all risk devolves into the Oedipal Mother, which is a sure path to serious psychological issues.