A wise man once said, if you don't think you're the best at what you're doing... you're in the wrong business.
No, that's arrogant, not wise. You should feel that you're dedicated at what you do, you should be serious about what you do, and strive to be as professional as possible. But when you start swaggering about and tossing bravado around like cheap champaign, claiming to be the best, you only endanger yourself and others.
It's not about being the best. It's about being professional, and safe.
Don't think for a moment that the navy has the corner on firehoses. You're being offered a position for which you're very fortunate, and you're doing what's necessary to get through it. Everybody trains, everybody gains experience, and in the bottom analysis, you're no different, and certainly no better, than the next.
Remember that, or it WILL kill you.