I found a notation that kiedy expresses precise time; gdy is less precise. ,but ,I do not know if there is a time you must use it, i think that when you use it it is used to be grammatically correct.How many people would notice?
I found the audio hard to understand--the "gdy" is barely by pronounced at all but quickly elides into the moja.
Is this how a typical Polish person would pronounce the sentence?
Yes I think GDY is pronounced right in this sentence. (Babcia on the other hand is not-I do not think stress on BABcia should be so intense)
I never called my polish grandmother babcia growing up. I don't know the exact spelling but it was pronounced like boo-sha.
Babcia here is the subject of that clause of the sentence, so it takes the nominative.