Teeth Whiten?

I admit that I have the poor smile because of my teeth. It is not because my teeth are not aligned but because they are yellow (not too yellow). But my teacher in Science told us that yellow teeth are the strongest teeth. I would probably believe her for making such a remark but no matter what information that is, it saddens me. My friends recognize my "yellow" teeth (not knowing that they are strong even they are yellow). This intimidates me. I feel outcasted and conscious. I know they have the perfect white teeth and can glowfully smile to the crowds. Me, too little to show off. I can't even smile publicly. Much more, I prefer to hide my smile when a friend told me about the problem of my teeth. Her warn awares me not to confidently show my teeth...:-(! Of course, I need to talk but maybe what she meant is that I should be aware of what other people might say if I will talk in expose. Huh...! So sad why I have the "yellow" teeth. Nevertheless, I will find ways to have them whitten. It really downs me!