An old saying in England was -- You are not an experienced rider until you have fell off 7 times !
If I were to abide by that rule, I would be doing grand prix. Ah well I suppose it's just an old saying trainers tell their students to scare them a bit.
It's very difficult to put a label on a rider, some may be amazing in the saddle but are of little knowledge in the barn, some may be doing piaffes and pirouettes but have never jumped anything larger than a cross rail. But this is how I generally view riders. Green as grass-
very little interaction with horses, most involving petting zoos. Ridden once or twice with a trainer. Beginner-
Can tack up with minimal assistance, rides once a week with a trainer, confident at the walk, trot and beginnings of canter. Can properly post on correct diagonals. Is familiar with parts of tack, horse, and can be left unattained for short periods of time while grooming or leading a horse. Novice-
Walk, trot, canter on correct diagonals and leads. Confident in two-point and no stirrup work. Capable of jumping a simple 2' course or complete an intro test with 60%. Requires little to no assistance while grooming, tacking, leading ect. Intermediate-
Confident in all gaits, has ridden an array of horses-not just school horses-can sit most rears, bucks, bolts ect. (because lets face it, even the best riders fall) Can ride a green horse with assistance from trainer, complete a full course of around 3'. Complete training level in a show and schooling up to second level movements at home. Framiliar with worming, feed, medical, hoof, problems ect. Advanced-
Started a horse or taught the basics with help of a trainer. Can handle most if not all of unexpected situations under saddle as well as around the barn. Framilliar with medical situations and how to deal with them.Jumping up to 3'9' course or riding 3rd level schooling 4th movements. Professional-
Started one horse from scratch with minimal help. Showing competitively at recognized levels 4' and higher. Prix. St. Georges and up. Wins purses and trains horses for a means of income.
Of course many of you won't agree with that, it's just what I think and it plays off of jumping and dressage. Again why it is so hard to label riders, there are many people who have never been to a shown or jumped or done dressage that could be consider professional.