We have recently came across the topic of question tags at our lesson and at school my teacher isn't a native speaker and said herself she doesn't know, so that's why I'm asking here.
If I say "I'm lazy, aren't I?" That should be grammatically correct based on my textbook. They wrote there that "I'm lazy, am I not?" doesn't exist, it's incorrect. However, I found on the internet a few discussions where people used it. Another one said that it sounds just really old.
Is it really grammatically incorrect or just old? Or it depends on the region? I'll be glad if you express your opinion because I'm really curious. I think I'll still write "aren't I?" in the exams, just to be safe ... 😁

Question

BluePeter · Answer

“Am I not?” is perfectly correct English and is certainly not uncommon in usage. However, it does sound somewhat stilted and is usually used for effect/impact, giving extra force to a point of view being put forward. 
“Aren’t I?” is what you will hear us say in ordinary conversation. 
If you are going to be marked down for using “Am I not?”, then it is important to stick with what the examiners perceive to be the only option. However, you know the true position and you can be satisfied in that knowledge.

ChimaLuke · Answer

It’s grammatically correct but it’s old. Yes ‘aren’t I? flows so much better✅

ChimaLuke · Answer

Pleasure 🙂