Honestly, as someone who has never been in DKA, I imagine that it takes quite a long time to GET to that point… it can begin to happen within a matter of hours, but the full effect would probably take much longer than that.
It’s going to vary for everyone, based on how much residual beta cell function you have. Some people probably have enough that it would really take a lot of things going wrong to send them into DKA, while others may be much more sensitive to it.
I went about two months without insulin after the birth of my first child (after using insulin for almost 6 months) - mostly due to being mismanaged by medical “professionals” following his birth. No one knew I was a T1 and that I needed insulin… so of course they didn’t tell me to take it, in fact everyone told me to stop testing entirely after my pregnancy, since my #'s had returned to “normal” at the hospital (which happened with my next two kids as well, I needed next to no insulin right after they were born, but it absolutely didn’t mean that I was “cured”). I failed the follow-up GTT, which is how they knew I was still diabetic. It took another several months of dealing with an idiot of a doctor (convinced I was T2 and did not “need” insulin) to finally get a T1 diagnosis (based on antibody testing) and know for certain that I needed insulin, but I had been self-medicating for a while before that.
I will admit though, that there have been MANY days in the past 10 years where I’ve had a “I hate everything” day and I haven’t taken much of any bolus insulin. In those cases I’ve always had basal insulin on board, and I end up playign “catch up” at the end of the day and correcting the high (mostly so I’m not up all night peeing). I’m not suggesting that doing that is a good idea, but I just wanted to let you know that you are NOT alone, and it’s something that we all deal with at some point.
You might consider going to a counselor to work out why you feel the way you do - you might find that you feel a lot better for it. If there is a certain aspect about your D management that you can change, that would make a difference for you, that is also something you can bring up with your doctors.
I was also diagnosed as a young adult, and I honestly think that being diagnosed at that age is a little harder than any other - you’re still figuring out who you are and what you want out of life, and you are suddenly thrown a giant curve ball, and it’s not fair… not that it’s fair at any other age, but I do think it’s probably easier to adapt if you are younger, or just a bit older. You WILL get through this though… just remember that you’re not alone, and if the rest of us could do it, you can too