, I don't think that this is quest breaking. You had the chance to steal the amulet in the first place but you were too greedy. That's your problem. But apart from that there are other ways to solve the quest (convincing her to give you the amulet or killing her)...
Yes, there is the argument to get her amulet as I wrote in my original post. And yes I do know that if I fail the rock-paper-scissors mini-game I can just reload, however considering some might want to not reload anytime they get a bad result, they have to look at other opportunities.
The skill pickpocketing and the item "level" you can steal is determined by a combination of (value of item + weight of item), each level in pickpocketing gives you an increase in said formula. Quite a fine system in my opinion, problem is if I steal say a key at skill level 1 maxing out my limit, then I am prohibited from returning once my skill level is at level 2 or 3 e.g. and steal something else also.
My point is this: if there is such a system in place to determine what and how much you can steal, why also limit the total amount of tries of pickpocketing to 1? You already have a limit and you are not automatically successfull as I have been discovered.
So from a roleplaying perspective I will still advice to change pickpocketing, so that you can attempt to pickpocket as many times as you want, but you are "limited" by 1) the existing formula for weight and value, and 2) every time you try to pickpocket the chance of discovery goes up by X%
