Which has already been explained, ad nauseam, is not the same as calling you A kid. I know you might struggle with the fact that different areas of the English speaking world have idiosyncrasies with the way that they use certain worlds. However do try and broaden your horizons. Trust me it isn’t that big of a leap. I had to do it when I moved to the US.
Think of it as similar to dude in the US or guey in certain Spanish dialects.
Usually it is used as a term of endearment. For example when thanking someone. You might say “cheers kid”. You wouldn’t use it to insult however. Like you wouldn’t say “That kid over there is a moron”
Starting to get the idea now.....kid?