Prevent carrier from getting information?

Hi, so I have an iPhone an my carrier is T-Mobile, I'm a senior in high school and my mom pays my bill an she checks my call log and my texting log and my internet. I'm confused on why and how that information is even available? I turn my cellar data off and use the Wi-Fi when texting(iMessage) and browsing the Internet shouldn't that stop the information from being available to her? How do I prevent her from being able to see when I'm texting or browsing the Internet or using FaceTime?

And you say you are in High School? Call log is easy to check just by looking at the phone bill. This shows every single incoming and outgoing number for calls and how long they were. The SAME bill shows every single incoming and outgoing number that you are texting with. And yes you guessed it, shows how much data you are using too.

As far as iPhone info, if your family shares the same iTunes, iCloud and Apple ID info, that is how she is seeing anything above and beyond call/text logs and data usage.

Want to really stop ANYONE from knowing how much you use your phone? The 100% sure way, is to get you own individual account that you and you alone are paying for. Not sharing any account info with anyone else. But seeing as how you are in high school, you are still in give me everything mode. So the likelihood of you paying your own phone bill, is about the same as me sprouting wings on the a breaking news story and flying around the Space Needle at noon.