No, your use of "refer" was not perfect. How do you REFER TO others in a group. The above answers were fine. I live in Texas, so when speaking I usually say "y'all."

I agree with others that "everyone" is a good alternative in many situations. What does everyone think of that? What do you guys think of that? But personally I can't think of many cases where I would consider "guys" either disrespectful for reasons of age or sexist. It's pretty neutral and universal in my circles. In those same circles, words like you'se and y'all would never be used. We know they exist from movies and books etc. Your use of "refer" was perfect.

It's less common to use 'guys' to refer to females unless you are referring to a group of males and females together. In that case, 'guys' is an informal substitute for 'people'. If you're talking to people directly 'guys' is acceptable, e.g. 'Hi guys!' even if some (or all) are female. In this context, it means 'friends' or 'acquaintances'. You wouldn't refer to a group of females indirectly as 'guys' e.g. 'Look at those guys over there'. You'd say 'ladies' or 'girls' or 'women' (assuming you need to mention their gender). As a rule of thumb, I'd say people use 'guys' when addressing a group containing males (with or without females) OR when directly addressing people informally, such as friends. In a more formal or less familiar context, you'd refer to a group of females as 'ladies' or 'girls'. You can also replace "guys" and "you guys" with "everyone" in your day-to-day speech. That's very similar to replacing "guys" with all or you all (or even y'all). If all or everyone seems too "big" for just two people, then you could substitute both. Hope this helps! Teacher Alicia

This is a fun one. In the southern US, you would refer to a group of people as “y’all”. In the northeastern US, “youse” is common (but informal). Saying “you guys” will be understood everywhere, but is very informal as well. If you’re unsure, just use “everyone”, as in “how is everyone doing today?” or “I hope everyone is feeling well today”.

'Guys' is a bit non-PC to a mixed gender group, although it is still quite common. In other words, avoid it if you don't want to be labelled as sexist. You could say 'people', 'everyone', or 'ladies and gentlemen' depending on context and the level of formality. How to deal with different ages would depend on the culture. We don't typically have as much age-based language and respect as you do in China.