Don't think I can improve on Ursie's excellent advice, Anna.
This is often where beta readers can be worth their weight in gold. Write the story as it emerges, don't get too hung up about whether the pacing is right, etc at that stage. Your beta can tell you as they read it over with a fresh eye whether they think A, B and C is necessary or not, gets in the way or not, and then you can decide from there what you want to keep or discard.
Good luck!
LabRat
(who is good at dispensing this kind of advice but lousy at practising it...)