It's entirely possible you've always had the aptitude. Indeed, having recurring instances to deja vu is one indicator. That said, not everyone's able to wake up that particular talent - practicing magic as you have over the past few months might've brought it out.

And as for this future... [Merlin's expression doesn't change, but his tone gains a somber inflection. By now, Watanuki might be able to tell he's thinking about Arturia and Camelot, again.] We don't always know how we'll arrive to this point, or how it will turn out after. Some particulars can change thanks to our choices, but others - ah, not so much.

I promise you they won't catch sight of the two of us. While we're here, however, we might as well maximize the opportunity. [He makes a sweeping gesture with his arm to indicate their surroundings.] What - or who - else do you see?