You shouldnt base your beliefs on songs about christianity. If you really want to learn about the faith it is best to read the bible. Starting with the new testament though. And possibly find assistance with a pastor. A lot of churches do bible studies, especially ones near colleges like to cater towards young adults/teens (im guessing that would be your age group). Probably would want to start with a church that is more laid back. If your sister is christian too I am sure she can help out too.
I was raised catholic and have lived a somewhat christian life, still consider myself christian, just havent been the most of devout ones. If you have any questions though you could shoot me a pm, or im sure any of the christians who have posted previously would love to share more aswel!