An opinion cannot be wrong. It can be disgusting and abhorrent, like homophobia, racism, sexism and so on, but it isn't wrong - It is simply an opinion. The "facts" that form an opinion can be wrong, but the opinion it's self cannot be.
If something is not true and you believe it, then your belief is wrong.
For something to be deemed "true" then it needs evidence. Most, if not all religious beliefs don't have any real evidence. They call it having faith. I call it wishful thinking.
So yes. Adults CAN be wrong in their beliefs, just like children.
People think that when we become adults we make a complete 180 from being ignorant to wise so on and so forth. But adults still have beliefs that are just as far fetched as the childrens beliefs. The belief that a perfect god who knows everything and can do anything came from nothing and created matter and energy from nothing is far more implausible than an all knowing man being born into the world who can visit every house in the world in one night. So obviously adults are just as foolish as children when it comes to religion. Most people will believe any religion that their leaders give them and history proves that. Only less than .1 percent of religions can be true as there are more than a thousand religions whos gods claim to be the one true god. Facts dont contradict facts and thats why i believe in science over religion. Science facts dont contradict any other science facts and if they did than some of these "facts" wouldnt be facts.
Between children's beliefs and adults beliefs.
Children will believe without factual evidence, they will believe something if they are told it is real.
Adults beliefs are much deeper. We don't just blindly follow what we are told but we research and study the history and come to a logical conclusion based on our research.