Not every Christian faith goes this way, but mine goes with the idea that Adam was given three commandments. First, multiply and replenish the earth. Second, cleave unto your wife. Third, do not eat of the tree of knowledge. And until he knew good or evil, he couldn't do the first(aka breaking the third), and once Eve ate from the tree, he could only follow the second by breaking the third. I personally see the tree of knowledge bit being a symbol that they were ready to take on the world, before that, they couldn't even if they thought themselves ready, and after that they HAD NO CHOICE BUT TO whether they were ready or not. Also that as Adam didn't KNOW good or evil, he wasn't actually capable of sinning, he didn't understand enough, I've heard secular arguments that this can be looked at as the cost of sapience, now that we can think to the future, we must prepare and can't live in the moment.
But, no religion should be forcing you to stay in it if you don't like it, though some do have difficulty in getting your name out of their records as a member, you're not forced to follow their precepts.