Instant Trigger vs Delay Questions

I'm sure this has been asked a million times and I've googled and googled but maybe it's my age lol. I have all my doors/windows on "instant trigger" because I'm a scaredy cat, but when I came home today and didn't disarm from my app first (it was on the "away" feature), I figured I had a minute to get in the door and deal with the 30 sec delay I had created. I was wrong. The alarm went off, I received a text and am wondering is it because of the "instant trigger" there is no time to set alarm to off? I'm not comfortable with using only a delay where someone could come in and have 30 secs or so to kill me and my dog....Thank you from an older lady :)