Holiday with bf parent help

I know some girls here are in emergencies and need much more urgent help from the community on the app so only read this if you have time, are bored or fancy helping a girl out :))

Me and my boyfriend are going on holiday next summer for a week. At the moment I’m 17 and he’s 18 but we’ll both be 18 by the time we go. We’ve booked accommodation and paid and it’s non-refundable and now we need to book flights. I need my passport details so we can sort the tickets.

My parents will 100% not be okay with this holiday but I’ll be 18 and am paying for the whole holiday myself. They have never let me and my boyfriend spend a night with each other and we’ve been together nearly 3 years. I’m not 18 yet but I don’t get her impression that their opinion on us staying together will change when I am. They were okay with the idea of me going on a girls holiday but that’s collapsed now so this is my only plan for next summer so I can’t wait. I haven’t told them about this holiday yet, I was going to I just didn’t know how to. I know it will start a massive argument and my parents take my phone and my car off me and get really confrontational and its horrible so I’ve been dreading it. I now basically need to because I need my passport before flight prices start going up and idk where it is and I don’t know how to go about it. I don’t know whether to “ask” for their permission for the holiday but I know they’ll say no and we’ve already booked it.

Basically I just wanted some help on how you guys think I should convey this conversation about my holiday with my boyfriend in summer to my parents. Or any top ideas on other reasons why I would need my passport although that would just be postponing the holiday conversation. I will be 18 so a legal adult and will be paying for the whole holiday myself so they can’t really stop me but I obviously don’t want to start a massive war with them and I don’t want to just announce that I’m going so any ways on wording it.

Thanks for any help girls x