but she's so used to bribery this is probably an extortion attempt. So the OP has used rewards based behaviour management quite often. This is usually a more successful strategy than sanctions for children on the spectrum.
She likes the power of being able to wreck it for everyone else The OP posted this when she was angry and stressed. We have no idea what she really means.
She's sitting in her room smiling, and she's said to another child that's she's already ruined the holiday. If she is very stressed about going away she is very likely to want to prevent the holiday from happening.
I don't see any of those little snippets as reasons for the OP not to look into the possibility of AS. The fact that she has form for backing out of activities at the last minute, which is just about all the information we have about her, is, IMO a reason to consider that she may have a difficulty with transitions and new situations both of which are common in AS.
I'm not saying that the OP's DD has AS. I couldn't possibly know this with the tiny amount of information she has shared or indeed any amount of information about a child on an internet forum.
I am saying that, as the OP is struggling with an aspect of her DD's behaviour which seems to make little sense and isn't usual in 12 YOs, it is worth her considering whether AS is an explanation. She needs to read up on it and think about lots of aspects of her DD's behaviour and development and then decide whether to request an assessment based on that information.
It is entirely possible, even highly probable, that she doesn't have a developmental disorder and there is some other explanation for her behaviour.