Clarity on what I need to do with the User Age Group API

I agree with the  frustrations here. Here is what I am about to implement. Hope this helps. Uses language locale and considers app content rating in that locale which you will have to hard code like I did, and varies depending on your app. Also caches entitlement and if the age was appropriate in player prefs. Then you can reference it offline and throughout your app and only have to run this on the load screen. Useful to check age category later in the game if you have achievements/leaderboards etc so you don't use them if it's a child.

void Awake()
    {
        try
        {
            Core.AsyncInitialize();
            Entitlements.IsUserEntitledToApplication().OnComplete(EntitlementCallback);
            UserAgeCategory.Get().OnComplete(GetUserAgeCallBack);
        }
        catch (UnityException e)
        {
            Debug.LogError("Platform failed to initialize exception.");
            Debug.LogException(e);
        }
        if (PlayerPrefs.HasKey("ageIsOk"))
        {
            if(PlayerPrefs.GetInt("ageIsOk") == 1)
            {
                ageIsOK = true;
            }
            else
            {
                ageIsOK = false;
                userAgeErrorUI.SetActive(true);
            }
        }
        else
        {
            ageIsOK = false;
        }
        if (PlayerPrefs.HasKey("isEntitled"))
        {
            if (PlayerPrefs.GetInt("isEntitiled") == 1)
            {
                entitled = true;
            }
            else
            {
                entitled = false;
                entitlementErrorUI.SetActive(true);
            }
        }
        else
        {
            entitled = false;
        }
}
void Update(){
if(entitled && ageIsOk)
{
//run app
}
}

private void GetUserAgeCallBack(Message<UserAccountAgeCategory> msg)
    {
        var uaac = msg.GetUserAccountAgeCategory();
        if (!msg.IsError)
        {            
            string location = Oculus.Platform.Users.GetLoggedInUserLocale();
            int minAge;
            if (location.ToUpper().Contains("EN-US") || location.ToUpper().Contains("KO") || location.ToUpper().Contains("EN-AU") || location.ToUpper().Contains("PT-BR"))
            {
                minAge = 10;//child
            }
            else if (location.ToUpper().Contains("DE"))
            {
                minAge = 12;//child
            }
            else 
            {
                minAge = 16;//teen
            }
            if (uaac.AgeCategory == AccountAgeCategory.Ch)
            {
                UserAgeCategory.Report(AppAgeCategory.Ch);
                PlayerPrefs.SetString("ageCategory", "Ch");
                if (minAge < 13)
                {
                    ageOK = true;
                    PlayerPrefs.SetInt("ageIsOk", 1);
                }
                else
                {
                    ageOK = false;
                    PlayerPrefs.SetInt("ageIsOk", 0);
                }
            }
            else if (uaac.AgeCategory == AccountAgeCategory.Tn)
            {
                UserAgeCategory.Report(AppAgeCategory.Nch);
                PlayerPrefs.SetString("ageCategory", "Nch");
                ageOK = true;
                PlayerPrefs.SetInt("ageIsOk", 1);
            }
            else if (uaac.AgeCategory == AccountAgeCategory.Ad)
            {
                UserAgeCategory.Report(AppAgeCategory.Nch);
                PlayerPrefs.SetString("ageCategory", "Nch");
                ageOK = true;
                PlayerPrefs.SetInt("ageIsOk", 1);
            }
        }
        else
        {
            Debug.Log(msg.GetError());
        }
    }

    private void EntitlementCallback(Message msg)
    {
        if (!msg.IsError)
        {           
            PlayerPrefs.SetInt("isEntitled", 1);
        }
        else
        {
            PlayerPrefs.SetInt("isEntitled", 0);
        }
    }