I’m confused about River Songs timeline
So I just finished season 6 episode 2 of nuWho and up till now I thought the doctors and Rivers meetings were just completely random, but in this episode River says that their timelines are perfectly linear - but in opposite directions. In which case, what is the point of “Have we done X?” Every time they meet it will technically be with versions they’ve never met or done anything with.
And in the Library episode, River says the last time she saw the doctor, he gave her the screw driver and took her somewhere on a date (I don’t remember where atm) which means they CAN meet out of “order,” which would make River an unreliable narrator in S6, which is fine since it’s her future. But if the doctor can do that the entire time, why doesn’t he do it more often?
I would try looking it up but last time I tried that I got spoiled on something pretty big. If this is something that can’t be explained without spoilers then don’t tell me, I was just wondering if there was something I misunderstood.
Edit: thank you for the responses, I seem to have taken the line too literally :)