This question is kind of like asking people which foot they have forward when they bunnyhop. It’s something that you just don’t think about. I almost guarantee that someone who has been riding for years will read this thread and then fall over next time they try to stop b/c they’re thinking about it too much.
The bunnyhop question came up on BF several years ago. More than a few members reported an inability to hop for several days after because they were trying to figure out which foot to put forward.
Anyway, the more you ride, the easier it will get. I prefer my fixed to my geared when getting on and off. On the fixed, the pedals are always where I want them to be (or they will be if I wait half a rotation). On the geared bike they might be anywhere, and they might rotate backwards when I put weight on them. That makes me uncomfortable.