If your unsure, then a lot more mistakes can happen during CTB.
Even if it's for the sake of "If I do it, I need to succeed"; try to get some time for yourself. It may be the last decision.
And spoken for the DID part: I have a form of dissociation with alters BUT not separated, so I'm still the same person, share the memories etc. I just have different versions of myself and switch (mostly uncontrollable) between them.
But what I know is, if I try to just decide for us all; there're always parts who strictly are against it and try everything to sabotage it.
So no matter what you do - try to find some consent? Or at least to listen to their needs. Not that you HAVE to come to a conclusion for everyone. But it can also help finding out what to do next.
And bpd sucks - I had multiple impulsive attempts. Would not recommend. So if you see a chance to stabilise that a bit - take it.
And I mean; as you said you can always talk yourself out of that situation and how would they know that you're still doing bad if you convinced them you're fine?
And if it helps and you decide to not CTB: that's valid and great as well!
Because ... You're doing better then, right?
Don't rush through that process.