I think that is likely to result in confrontation. As a general rule I'd suggest always discussing this with your manager first - if you communicate with them directly it may turn into an HR issue where your direct communication would be highly scrutinized.

My advice would be to talk candidly with your manager and express what has happened already and how you feel about it - then my suggestion, as a manager myself, is to suggest a meeting with you, her and the technical decision maker (whether that's a manager or a tech lead) to discuss the scenario and different solutions you can take. It is extremely unlikely (and generally unhealthy for a workplace) for the final path to be entirely your idea or hers - compromise is the expected outcome here. Compromise breeds further cooperation so even if your entire solution is just outright better a good lead will make sure opinions from everyone are incorporated into the plan. You'll end up having a brainstorming session essentially with a chaperone to make sure neither person is disregarded and should come out better for it.

I've been a dev (junior through senior), I've been an architect, and I've been a manager - I want to stress that the technical outcome of this decision is usually secondary to mending the team rift. I have, as an architect, conceded to a bad plan to give confidence to an intermediate developer (and made my boss aware of everything going on) and then immediately set out building a plan to fix it once the solution went live (and no, i didn't "I told you so" or anything, I just silently built the plan and made sure we could easily pivot our implementation). Working together and building a positive team environment is extremely important.