Yeah, I can remember when I was your age I felt so well rounded and my outlook was so 'right' that I honestly thought that every one else was stupid.
But, then one starts to gain more experience in evaluating ones own actions and one begins (at least I did) to see that the evidence you percieived as pointing to ones own beliefs being 'dead on' accurate is in fact a cognitive distortion.
We need this cognitive distortion to be biased towards our 'righteousness' when we are in our youth; otherwise we will get beaten down by the pressures of this difficult period of life.
Imagine how we would fair with our university chums if we did not stick up for ourselves (even when as an older person we may conceed the point).
At some points in our life we need to be brash and unappologetic.
This builds self confidence and gives a locus of control to oneself, not everyone else our environment.
It sounds like you are starting to question if you are being as rational as you could be. This leads to us evaluating our assumptions and core beliefs.
Once you start self-evalution you are on the right track to adpating your attitudes and beliefs and this is totally appropriate.
If we don't formulate and reformulate our cognitive strategies for interacting with the world (as it seems you are starting to by actually righting this post) you may as well read a book on what attitudes and beliefs to have and stick with that inspite of any feedback you recieve.