Can I Question Everything I Believe?

Once I believe in something, it becomes the truth
That is the only way I can define truth
And I hold so many truths
But are my truths absolutely true?
Are my truths really changeless?
Are beliefs relative or absolute?
They must be relative since everyone has differing beliefs
So then what is absolutely true?
Can I really start questioning my world of beliefs?
Am I too scared that my world may crumble?