use javascript and embedded data to randomize question formulation

Hello, I am new to Qualtrics and I am struggling to understand how changing the embedded data works. I have the following situation. Let's say we have: Q1: What's your best friend's name? Q2: What's your brother's name? and in Q3 you want to ask how old is either the brother or the best friend (picking one of these randomly). What I am currently doing is first in the SurveyFlow I create an embedded data called "chooseRandom" (with no preset value), then, in Q3 I ask "How old is ${e://Field/chooseRandom}?" and I add the following javascript function: Qualtrics.SurveyEngine.addOnload(function() { var arr = ["${q://QID1/ChoiceTextEntryValue}", "${q://QID2/ChoiceTextEntryValue}"]; #create an array with the two names Qualtrics.SurveyEngine.setEmbeddedData('chooseRandom', arr[Math.floor(Math.random() * arr.length)]); #set 'chooseRandom' as one of those two elements }); However, when I preview the survey the question shows simply as "how old is ?" I think I'm simply not fully understanding how this "setEmbeddedData" function works. This is a simplified case, ideally I would want to have more conditional choices when creating the array from where to pick an element randomly, however I think if I understand this part, I can figure out the rest. Thanks in advance!