Our seven-year-old daughter was thrilled when we took her to Disney World for the first time, and she headed straight for Space Mountain.

I worried that the roller coaster would be too scary for her, but she insisted.

To her delight, we rode it twice.

The next year we returned to the Magic Kingdom, and my daughter, now eight, again dragged me to Space Mountain.

As we stood in line, though, I could see her soberly studying the signs that warn about the ride's speed.

"Dad," she said, "I don't think I want to go."

I asked her why she would be nervous when she had enjoyed herself last time.

She replied, "This year, I can read."