If is a rope tows in a beginners area they usually aren't too fast or intimidating. Both my daughters have been using rope tow since they were 4 or 5 years old. Now at 7 and 10 years old they seek out the rope two at one of our go to resorts as a quick way to "ski laps" in the terrain park. While you should be prepared to the "between the legs method" for a fast primary rope tow if you can find a slow kid friendly tow I suggest what my wife calls the "pitcher and catcher" method of teaching how to use a rope tow. Here's how it goes:
Step 1 -- One parent or adult rides the tow up the hill. It need not be all the way but at least a good way up and at a place where it is easy to dismount. This parent is the "catcher"
Step 2 -- The second parent or adult (the "pitcher") stays at the bottom of the hill and helps the kid mount the lift. If the parent/adult is not a strong skier this may be best accomplished without skis. If the parent/adult is a strong skier and can keep their skis on they can follow the kid up the mountain. It seems all kids want to stand with their skis perpendicular to the rope tow and as soon as they grab the tow it will pull them over. The key to success is getting their skis parallel to the two and sometimes it helps if the "pitcher" gives them an even push forward to get them going.
Step 3 -- The "catcher", waiting up the rope two, receives the kid and helps them get clear of the lift. Again this is sometime easier without skis on for the adult if they are not a good skier.
Step 4 -- Ski down the mountain together.
My wife and I did this for about a half dozen laps per kid when they were this age and they picked it up right away and quickly didn't want mommy or daddy's help. Have fun and make a game out of it. This is a great age to start your child skiing.