Only an “authority” can be either fallible or infallible.
Your beliefs, which means “what you understand as the items of your faith”, just like ours, can be either correct or incorrect (true or not).
If you set yourself up as “an authority”, then you CAN be either fallible or infallible. You most likely wouldn’t call yourself “infallible”, I would guess.
Since no Catholic is allowed, or for that matter WANTS, to set themselves up as “an authority”, we Catholic people don’t have the opportunity to BE infallible, and are entirely fallible in stating opinions (interpretations) as actual truths.
You probably think that NOTHING but God Himself can be infallible, which is also what Catholics believe, and in much the same way that you believe that (as via the actions of the Holy Spirit), but we insist that God speaks to us infallibly only through the agency of the Church (via the Holy Spirit) while you can communicate infallibly with God individually.
The consequences of those two views of how God accomplishes His will is what we see in the world today.