What can you do so far? I think that this would be how to split the groups, but i've added in an extra one:

Beginner: Someone who has little or no experience in riding. A beginner probably knows how to walk and trot, turn on circles, change the rein etc. Just basically everything simple that you are taught when you begin to ride.

Novice: Someone who has been riding for a little longer than a beginner. A novice can walk, trot and canter and perform basic school movements, and maybe also a very small jump. A novice will know how to ride a little more cleverly than a beginner would, for example, they can keep a better contact with the reins and keep in a good position in the three gaits.

Intermediate: A good rider who can probably master all four gaits and jump higher and longer jumps than a novice could. They probably know how to ride a basic dressage test, and whilst riding will be thinking about a forward movement, softening the hands and striving for absolute concentration from the horse.

Advanced: Someone who has mastered all the gaits, can jump a course of fences whether solid or moveable, knows some more advanced dressage moves such as rein back and is very confident in riding any horse that they are presented with.

I hope this helps. Do you ride western? If so, then this might not help as I've based it on English. But if there's anything you don't understand then don't hesitate to ask