If you or your potential skater of any size or age has a problem with the little test above, don't decide to give up on inline skating. Most children and adults can learn to do these things off-skates with a little effort and practice. Once standing un-assisted from both furniture and floor level is mastered, practice balancing on one foot at a time in flat shoes or stocking feet. Try to work up to 60 seconds per foot, to re-set your internal human gyroscope.
If your age or size does not prevent these off-skate activites, sign up for instruction with your nearest parks and recreation center, skating rink or inline skating group. Most inline instructors can teach you how to stand up and maneuver on skates... as long as you can manage and balance your own weight off-skates.
How to prepare for inline skating lessons: