Pointing out that you're shy never seems to help calm your nerves for some reason. Its also hard to brag when you're not a boastful type. My former boss got upset at me one time when she was introducing me to some guests as her "data expert", and I quickly muttered "oh, I'm no expert!" She looked at me with an annoyed expression like "How dare you question my judgement!" I learned overtime that you have to own up to your achievements and not downplay or deny the grandiose claims of potential or current employers for your professional well-being. Its all a matter of acting.