The option is just "I have something I want to show you" and then she follows you out there. If that isn't there you can punch her and have her chase you out there, although she might flee by default. If you're on the PC you can go out to the dinosaur and use the console to move her to you - once she's there the event should trigger. Also keep in mind it has to be when Boone is there, so you may just not have the option if Manny's in the dinosaur.
Make sure Boone is in the Dino when you try to ask here.