The best service I've had was calling the Trans Lifeline. I spoke with a peer who actually got it and made me feel understood and less suicidal. It certainly wasn't perfect but it was better than nothing. Plus I actually felt safe talking to them since they have a policy against active rescue, meaning they absolutely will not call authorities without your explicit consent. I felt free to actually tell someone how I'm feeling without fear.
I've also seemed to have had a better-than-average experience when I went to a psych ward. It wasn't amazing but it definitely kept me alive and I did leave with more tools than when I entered. Before they transferred me from the ER MHU to the actual psych ward was pretty bad though. The staff were not trans-competent at all and I had to share space with a transphobic patient. I actually felt like killing myself even more after I got there lmao. I should mention that I did voluntarily admit myself fully expecting them to have to incarcerate me. It's not like my freedom was ripped out from under my feet after divulging intense suicidal ideation & plans. I have had this happen before and oh god do I never want that to happen EVER again. In this case I knew what I was getting myself into other than the transphobia I encountered. That caught me off guard in a moment where I wasn't in a headspace to advocate for myself.
I have called a crisis line that does do active rescue but I had to guard what I said so much and didn't feel safe that it was almost pointless. I would've had a similar experience talking to a friend about something boring like the weather. I wouldn't call them again. I also tried their text based service but honestly that literally felt extremely insincere like they were copy-pasting from a script so I just quickly told them I felt much better and discontinued the conversation. That felt like a kick in the gut and I actually felt even more suicidal after. I ended up talking to a friend which after which helped a lot more.
I've never called 911 for myself, although I've had many times where I probably should have. I really just want to avoid a traumatic run in with the police. I don't trust them to have any clue how to handle a mental health crisis with the compassion and care it demands. I'd have a higher chance of being shot, which strikes me as funny tbh.
I'm sorry you had such a shitty experience when you were twelve. That's an awful thing for a kid to have to go through. That must have been such a dehumanising and helpless feeling. I wish I could give little twelve year old you a hug and comfort you instead of having two armed racists show up at your bedroom door.
I hope you've had a restful night and today treats you with kindness. Try to be patient and loving with yourself. You deserve it :3