Complicated Relationship

So my best friend, Jeff, and I are dating. We aren't official yet and we plan to be when I turn 18 this summer. He's 19 so he just wants to be safe. My parents have forbidden me from seeing him, but I love him. He's been my best friend for forever and he has always been there for me. I couldn't bear it if I couldn't ever see him. He is planning on talking to my parents, but I don't know how it is going to work out. I'm really scared and would like some encouragement and/or advice please