Welcome to the wonderful world of owning a Velcro bird!!! There is absolutely nothing I would recommend you do to prevent her from been there. GCCs live to be on our shoulders! Nothing brings them more pleasure than that and, as far as I am concerned, if that is what they like, that is what they will get. I have had four GCCs altogether, three were rehomed (a pair that bonded with each other after they came to me and a single, mildly handicapped male that went to a couple who stay home all day long), the fourth one, a female with Hunter's syndrome, is still with me and has a boyfriend of her own (an old, severely handicapped, ex-breeder wild caught peach fronted conure) but she still spends two solid hours on me (and that means either on my shoulder or hanging from my chest).
Now, if you are willing to allow her to ride your shoulder for as long as she likes and the problem is that, say, at noon or in the evening, she needs to go back to her cage and would bite you when you ask her to step up from your shoulder, all you have to do is teach her to step up to a stick and always save her high value item for these occasions.