Bible and adultery!!!!!?

Admiring someone for their looks in itself is not a sin. It truly depends on how far your thoughts go and what is in your heart. Lust is a sin that falls under the commandement thou shalt not committ adultry. As Catholics there are degrees of sin, we used to call them venial and mortal. The term now is grave sin. If you are attending Faith Formation at your Parish I would suggest asking them to clarify this commandment for you. I think it is a common and appropriate question for anyone your age. Definately not anything they haven't heard before.