This is a great example of signs of being self-confident. When we stick to our morale values and don't let others sway our opinions, values and take care of ourselves and respect ourselves as a whole, we're self-confident.
Being book smart means you're really good in school and pick up things easily via educational means.
Having a high IQ means you're just very smart; usually smarter than most.
Having a high self-esteem would suggest that you have a high regard for your physical self.