Advice Please!

My boyfriend is 22 and I am eighteen. He and I have been dating over the phone (he drives a semi for work) for two months now. He invited me to spend a few weeks on the road with him. I will leave mid September. I've only met him once in person but things were wonderful. We talk everyday for hours. When I told my parents my plans, they freaked out on me. They are furious and think it's a dangerous idea. I see the potential hazard but I just want them to be accepting of it because it's what I am going to do. How can I ease their minds? I don't want to leave on a bad note. Thanks in advance for all advice✌🏼️