Found inappropriate content on my 9 year old ipod

I was coming into the bedroom when I heard my 9 Year old daughter running up the stairs. I noticed she was holding her iPod so I asked for it and checked the history. I figured she was hiding something and I immediately found several pages of explicit sexual content. We bought her an iPod so she could play her games and FaceTime her friends. We hid safari and downloaded her games for her. Somehow she found it and started looking at inappropriate content about 20 days ago. The stuff she was watching was so explicit that My heart jut fell.

I feel like I failed so much as a mother by not monitoring her device, I’m so lost with what to do. I cried all day and I’m not sure what the impact will be when she grows up. I feel that her innocence was taken and all just under my nose.