I found some stuff on my sisters dsi. What should I do?

Ok so my sister has a Nintendo DSi with flipnote studio on it. And people post songs on there. She's 11. And I've noticed her seeing some by Kesha and Britney Spears. So tonight I just had to and snuck on it and looked and she had Bruno Mars Grenade on there (which in my opinion isn't apporpriate for her age) and also 3 by Britney. And also like a g6. She doesn't know what these songs are about though. But she doesn't need to be exposed to it. And also I got on her web browser on it and she had been searching "what is toxic by Britney spears about?" and searching for the lyrics. She heard it from just dance 2. I know I shouldn't have been looking through it but it was for her own good. We are Christians. My mom doesn't know about this. What should I do? Should I tell my mon about this? Please help!