I am doubting that you can do extended and collected walk as they are two quite advanced movements in dressage.
Can you sit out a decent buck/cope with a hot horse etc.? As in my books experience comes from riding multitudes of horses with various problems, not just a quiet school horse.
Advanced to me is someone who is riding very high levels of dressage/whatever their chosen discipline is, and can ride out many of the problems horses can throw at you, someone who can get on any horse and improve it/train it etc.
Beginner is someone who has ridden only a few school horses or their own horse if they haven't had many lessons. They are still learning to balance on the horse, how to use basic aids etc.
I would class you as novice, going by what you've said without photos/videos. Though one cannot really judge without seeing you ride as you may be a terrible rider with no sense of balance that assumes collection is merely pulling a horse back so it goes slower, and extension is kicking it a bit so it goes faster ;)