privacy

okay so I'm 16 years old and today I discovered my mom has been using a website to see my texts, my Instagram posts, and other things. I understand that because I'm under her phone bill she's allowed to do this but I'm still upset. I have done nothing for her to not trust me. I don't drink, I don't do drugs, I'm safe, etc. i feel like I have no privacy in my house. am I allowed to feel this way?