how long does it take for a kid to learn how to ice skate?

This is one of these questions that doesn't have one answer. It depends on how you define "ice skate" and at what point they're done learning. One of my daughters who was 3.5 years learned to skate in about an hour. She still fell down a lot, but she could perform the act of moving her feet and gliding a little bit.

That's skating but it took several more hours before she could skate around the rink without falling. She learned more quickly than most. Usually after three or four lessons, a child will have the ability to move on their skates, but there is really a wide variation in how quickly they learn.

Typically kids will attain one or two badges of CanSkate in a year of lessons (Oct - May). Some kids do it faster and some do it slower.

So the answer really depends on the natural aptitude of the child, the effort they put into learning, and what level of accomplishment you want them to reach. To reach a national level as a figure skater, you can expect they'll likely be looking at 10 or more years of training.