DnD rant

I have to get this out somewhere so I don't explode on a friend. 

We're a trio that has oneshot DnD sessions once in a while. So far most sessions were hosted by friend2, L. I've hosted one before, meanwhile friend 1, F, has never prepared a session- which is fine, neither me nor L ever minded. BUT

For each one shot session we prepare new characters including stats. Now, me and L were always very quick to prepare for each others sessions. F on the other hand always takes her sweet ass time, despite it not taking a long time at all. And not just that, she wouldn't even prepare anything unless reminded regularly by either me or L, and in addition, every time we do remind her, she gets irritated and annoyingly passive aggressive. It's so rude and disrespectful to me. Everything is prepared for her, planning oneshot sessions is a lot of work and she gets to enjoy the game while making the progress much harder. PLUS me and L have always bent to her needs- planning the session based on her schedule, not ours. 

It's so annoying to me, I've tried talking to her about it on multiple occasions just to get told off about not stressing her out. We have another session on sunday, and I think it will be the last if this doesn't change.