How do you tell the difference between manifesting something and predicting something?

Before Christmas, I had been thinking about 1) playing the game Taboo, and 2) buying my girlfriend one of those little hot tub massage thingies for your feet as a Christmas present (really I would have used it for myself, which is one of the reasons I didn't go through with the purchase).

Then on Christmas day, her sister gave us Taboo and her parents gave her the hot tub massage thingy. I hadn't told anyone about my thoughts beforehand. We've never talked about playing Taboo with her sister, and the foot massage hot tub thing is totally out of the blue. I'm inclined to believe this is more than coincidence, but did I manifest these two Christmas presents or did I just predict them? How can I know?