Don't you see the problem here? When you read the bible, you are just as prone as anyone else to error. You a fallen, fallible man, read the bible and then you say "Aha! I have found the infallible truth!" How do you KNOW you have not made an error? How?? You are just a fallible man like the rest. So why should I pay a bit of attention to what you say the bible says?
The whole idea of private judgement is irrational. It does not work. It has not worked. It will never work. You say you trust only in Christ, but it is YOU who is doing the trusting, and you are fallible. So how can you know that you are really trusting Christ and not letting your own will interfere? You don't know. If a teaching is not infallible, then I say, the hell with it.
NEWSFLASH!
IT'S NOT THAT DIFFICULT TO UNDERSTAND THE BIBLE!
But I guess it might be a greater challenge for catholics since they were forbidden to read the Bible until 1952, when the church of Rome decided the unwashed hordes could actually follow the text on their own.
You have a lot of catching up to do, so I can understand your need for assistance.
It is also unbiblical.
However, individuals who have "the mind of Christ" will lean less and less to their own understanding as they become more and more spiritually mature Christians.
Unlike "those [individuals] without the Spirit", they are the only ones who are able to understand "the things of God", because they are spiritually discerned.
God says that those individuals without the Spirit are relativistic, man-centered fools and view his absolute truth as "foolishness".