yeah, i'm in the same situation you are khawateen..
i have a younger sister, but there is a big age difference between the two of us, that i find it hard to relater to her, and her to relate to me. while she's the typical 16-yr old, like you said..into everything and everyone - i'm so past that stage that it's hard for me to bring myself back to it. and she's still to young to understand that stuff that i'm going through - so it's hard for us to really communicate with each other..