First time flying😫

I'm 14, and me and my mom are taking a flight to P.A from F.L, and I'm so scared, I hate heights, and I'm pretty sure I'm over exaggerating but I watched so many movies in my life. I really want to go, because we are going for trial for my brothers murder case, and it will be the first time of me seeing my sister who ran away 2 years ago, and her newborn, and also my best friend I never said bye too. It's 110% worth it, but I'm terrified to go on the airplain.

Anyone have Advice?

Or if u where scared ur first flight, how did u handle it?