Why must girls do this??

So as a girl who always went home back from school,then frm clg then from uni...I finally got a job.

I joined this job with a grp of 15 members all of us being freshers..in 15 there r few boys when compared to girls..
One of the girls got a visa and she is gng to fly to another country in the 1st week of April. So the 15 planned to throw a party for her in a rented villa including a night stay. All the other girls parents were okay but NOT mine.

When I tried to discuss with them as to y they r not okay for me to go and stay out at night...they give all bullshit reasons...I don't understand y do girls have to CONVINCE their parents to go out either for one or a trip for 3 days?? I mean wts up with convincing?? Can't they understand? I gave the details and was honest with them n wt did I get in return?? （￣へ￣）