My thoughts and opinions have changed before and very likely will in the future. That means that current me holds some values that future me won't.
Sometimes that's to be expected - the situation today will be different from the situation tomorrow, so my positions need to change accordingly.
But some positions I'm holding are wrong now, I just haven't realised it. That's just how things are, and if you're always open to new ideas and willing to change your positions (given a convincing reason), then there's no problem. A common addage is to have "strong opinions, weakly held". This feels like a smart way to approach things but if most your opinions are weakly held then you have no deep convicions. Some of the greatest thinkers didn't hold their opinions weakly - they held onto them with deep conviction no matter what.