Surprisingly enough, Pike doesn't take it as bragging. Spock really is just stating fact.

"What kind of posting are you looking for after graduation?" After all, if Pike knows what Spock is working towards, he can better tailor his time aboard the ship. Some of the cadets that are onboard will be little more than worker drones in their department - and that's fine. Starships work because of drones like them. Not everyone is meant to be a shining star, some people are destined to simply be good enough. Spock doesn't really seem to be a worker drone, though.