It's not that they don't trust you it's that they don't trust the guys out there and they are afraid of what could happen to you, sit down with them and ask them why they don't want you dating, don't try and convince them by force, sooner or later they have to let you date.
You can convince your parents to let you date by earning their trust slowly. Find out why they are strict about dating and what age they think is appropriate for you to start dating. Ensure that your school grades are good tell them about boundaries you will create.
Well, if I was your parent, nothing would convince me that dating is a good idea as long as you are under my care. But I see this goes beyond that. To have guy friends, tell them you will always have your friends with you when you re with a guy friend, or will be supervised, so he cant try anything. And let them know him as soon as you are friends. As for texting, well, if I was your parent, perhaps I could be persuaded to let you text them if you showed me every single text. And that you dont text anything back without me authorizing the message.
You don't want to do date at this age, all boys do in school is cheat, sleep around, and just be rude boyfriends. At this age they don't have any respect and your parents know that, so they just want to protect you from being hurt like pretty much all high school girls are.