I think your problem, really, is that there is no one acting as a technical authority. There needs to be someone who is responsible for the final decision when the team is divided on which way to go.
It's difficult to develop software, especially in a business setting, purely by consensus. Everyone developer will have a certain amount of bias: maybe they want to use a technology they've never used before, maybe they want to take as many shortcuts as possible because they're feeling lazy, or maybe they want to re-write an entire library because "that's not the way I would have done it".
You need someone to control these tendencies.
I can see why your manager is hesitant to comply with your request. When you say to her, effectively, "the team isn't listening to me, you should promote me so that they have to listen to me" then obviously you've got a vested interest.
If you genuinely want the team to function more effectively, rather than just to get your own way because you're feeling stubborn, you should suggest to your manager that a role is created which has the ultimate responsibility for any technical decisions that are made. You should note the benefits this will have for the team. Tell her that you would be more than happy to apply for this role but ultimately that you will be happy as long as someone is responsible for giving the team direction that it needs.
You make it sound as if you think you're the most qualified for the position simply because you're older than everyone else. In my experience, senior developers tend to think this is true significantly more often than it actually is. Clearly, I don't have enough information to say whether this is true in your case but it's something to consider.