[General] What was your IELTS score when you were 18?

[Silverobama]

A young man whose got a 7.5 in his IELTS test told me he's not working part-time in a training school. His boss is not friendly and always looks down on him because his boss got an 8. This young man (my friend) is not very happy and dissatisfied with his boss because he thinks that his boss is always patronizing him. I told him that next time when your boss looks down on you, ask her the question "What was your IELTS score when you were 18?" (His boss is 45.)

Is my italic sentence natural?

 

[GoesStation]

It's okay. An American would probably ask "What did you get when you were eighteen?" Context has already established what you're talking about.