thank you for your reply. but where that choice is made in the game. i dont remember. do you remember? after which scene or before which incident that choice appear in the game?
As far as I can tell in the walkthrough, just be nice to Natalie on day 2 and 3.
On day 2: After the accident (Natalie falls on you during basketball practice), reassure her that you'll be fine, and after the nurse visit, tell her it's okay for her to come by during next day's practice (option "I don't mind...").
On day 3: Dinner at Harper's place. When Jamie asks you to, put your hand on Nat's leg (option "Do it"), and when you're about to leave, ask her to hang out with you sometime.
Those are the only options I can see in the walkthrough that involves Natalie. These should trigger the cinema dates on day 4 and near the end of day 9 (part of the 9.5/9.5.1 update).
Also, being nice to Coach Harper might help with her trusting you with Nat (maybe - I haven't actually tested this).