Long Distance..

My boyfriend and I have been in a relationship for a little over 6 months he asked me to his prom which is in April and he said he would get my plane ticket and everything. I would just have to get my dress, which isn’t a problem. The problems are my parents I don’t know how to ask them, or even tell them the whole story about him. They knew about him in the beginning but now I’m not sure. And I don’t know how they’ll react to me going for a weekend. Advice?