It's DH and BM's fault. Why are they allowing her to choose which high school to attend to begin with? I mean she's still a minor, why are they putting that big of a decision on a 14 year old?
As for SD being frozen about making decisions it probably stems from her childhood and the need to please all the toxic people in her life. Think about it, when you have a bipolar parent who one day loves blue and the next day loves red, you learn not to commit to anything because you don't want to upset the crazy.

People with anxiety have a hard time making decisions - they think too much about the possible ramifications of every decision and get stuck. I am one of those people. I do eventually make the decision, but not without a lot of hemming and hawing that drives DH crazy. It's not necessary always just a logic based skill, a lot of emotion gets caught up in in it too.  Especially when it might hurt either mom or dad.

Personally, I think DH and BM need to decide and say, "YSD, we think X school would be the best for you, for these reasons: does that sound okay? You've seen them both, do you have any strong objections?"

If this is a decision that BM and DH don't agree on, then no wonder it's hard for her.

I have no bios, so I never had the responsibility of teaching decision making to small kids. I did, however, emphasize concepts like cause and effect, good choices/bad choices, and weighing options to YSD when she lived with us as a teen.

Divorce often results in diluted parenting from one or both parents. I was a COD myself, and being on ST challenged me to look back over the period of my parent's divorce with new eyes. It's clear to me now that both parents lowered their game considerably before and after that event. 

I wish more emphasis was placed on parents being teachers, whose job is preparing their kids for adulthood. It's a task with measurable definitions of success, but I think many parents have never been introduced to that concept.

My second daughter didn't know how to decide and it showed up when she could talk. When she was a toddler I gave her a choice between two things and started her that way.  When she was in middle school I allotted my daughters a certain amount of cash for back to school clothes and took them shopping. She choose an expensive dress and made the choice to buy it and wipe herself out.  Next day she had a buyer's remorse meltdown and begged to return it. I made her keep it to teach her a lesson. ( mall was an hour away and I was not driving back for this drama).   She's 25 now and launched. 

It's a process and a major life skill that parents teach. Not everything can be learned at school.  Parents cause so many problems when they fail to parent. It's a verb, not just a noun.   

Have her make a pro/con list.  Put it on paper so she can see it. Start with that. 

I struggle with decisions. All sorts of decisions, from every day decisions to big decisions. I can over analyize an issue and see the pros and the cons and not be able to come down on either side. I am not sure that making pro and con lists of everything is always the way to find an answer. 

Big decisions like a school choice, can seem very daunting and life changing. What happens if you make the wrong decision? Will everything go wrong because the wrong decision has been made? As adults we know that she should be fine at either school, but that perspective came with time and experience. 

I think I agree with tog and that if sd has no real preference for a school that BM and your husband should choose for her if they can agree. Or perhaps just toss a coin??

How you you all teach your kids how to make decisions? So many of the skids never ever have to do this, the parents do everything for them.

Umm you do what you did like the example with the containers. Except you start at toddler age - do you want a bite of cake or icecream? Hurry up or no dessert. They'll figure it out soon enough. 

I was taught how to make decisions because I always had a deadline. My mother, who is a very bad decision-maker herself, was a big planner, so if there was a decision in my hands, she would give me a deadline by which the decision was needed and hold me to it. If I didn't make it, she would make it. That said, something like choosing which school to go to would not have been my decision. I could weigh in on what I wanted, but my parents (primarily my mom who was "in charge" of education) would have made that decision. Granted, my parents were not divorced, so they could more easily reach agreement.

In my experience, pushing decision-making off to the children in step situations is a manipulation tactic. Whenever there is anything that comes up that would change visitation, BM always has to say "I'll have to ask the boys to see what they want. I won't do anything if they don't want to do it." She does this even when the change was her idea. For example, three weeks ago, she asked DH if SSs could come to our home the night before they were supposed to under the CO. DH said yes, but they couldn't come over until 10pm because we would not be home. At first BM protested saying "why can't they come early and stay alone at your house?" And "don't they have a key to your house?" When DH didn't respond, BM finally said, "I'm okay if they go to your house at 10pm, but I'll have to ask the boys if it's okay." Um, okay, BM, it was your idea, but knock yourself out. I think she does this to make DH feel as though the kids might not want to see him or that any decision she makes is really just her looking out for them, but I think it's BS. 

My SD15 has debilitating fear of decision making. But she has strongly held opinions on clothes, room decor, etc. (not selfish or demanding, she just knows what she likes and dislikes) - so it's not that she's entirely passive.

But ask her to make her own decision on which path to take for a run, or how small to chop the vegetables - and she starts shaking and even will throw a small tantrum (followed by an embarrassed apology, at least).

I think it's an unhealthy fear of growing up: it's easier to throw all responsibility back to your parents when it comes to mundane decisions that do imply growing adult awareness and independence. But it's exhausting and infuriating to correct and encourage a teenager behaving like she's 5 years old.

That said, I wouldn't think the decision of picking a school, especially when it effectively implies choosing between parents, is appropriate for a young teenager to have to make.