My former sensei was given his nidan by a shihan in a passing sentence during the conversation that took place while the whole group was at a restaurant during a seminar. No testing, no ceremony... just a pad on the shoulder.
In those days - that's how it was done. These days we have a new system. Our Shihan is not on this earth any more and we have an organisation that can hand out the grades, and it is almost always done by testing in front of a panel up until 4th dan. On the very rare occasion recommendation is used for the lower dan-levels.
My point is - that even though it can seem that way, dan grades are seldom given without good reason, and - as other have mentioned above - most people feel a little disappointed once they get them. It's not in any way a revelation and you don't really feel enlightened. The hard part for giving shodan is to give it to people that are ready to deal with this strange feeling and stick to their training.
Don't prove your sensei's wrong in this decision. Just accept the gesture and the added responsibility that comes with this diploma, and continue practicing with dedication.
And most importantly... have fun