All I can say is you are wrong; it eventually catches up to you. Well, it did in my case late 50's, now early 60's but maybe genetic.
I have no other underlying issues that may cause it. Always been normal weight which I can't say the same for my sibling who is full on diabetic and 12 years older than me.
Father has it too but only on tablets.
Regularly eating carbs, sugar and sitting in front of a computer 8hrs+ a day at my day job and then too stuffed to bother exercise.
Thinking like you I'm thin but doing this for years and one day out of the blue a blood test shows blood sugar is high.
Then go do GTT test etc and doc says you better change your lifestyle. I now have a blood glucose monitor - I don't what to have that shyte!