I'm betting you really wanted to post "a real Christian," but thought better of it; I'm sure you wouldn't want to imply that those of us who celebrate Christmas are not "real Christians," would you?
I was raised on the "reality" of Santa until I was old enough to figure it out for myself. I consider my time of belief in Santa to be some of my greatest Christmas memories of my life, and something I would never wish had not happened. By the time kids figure out the truth, they are usually old enough to be able to handle it, perhaps barring some brief period of disappointment.
All kids are different and there are exceptions, but Santa is basically a HARMLESS myth that children OUTGROW.