What's the worst that can happen?

I'm a 16 yr old girl and i have a boyfriend that is 19. My parents like him and know about us dating. Well, one day my mama found a hickey on my and apparently was keeping it from my dad. well, she got mad at me and decided she was going to tell him. I know its illegal for us to have since i live in iowa but its legal for us to date. what's the worst that can happen? also my dad isnt my biological dad either and he never adopted me, he's just the guy my mom married.