When did the Youthful Worthies start to mingle with the Little Flock or with the Great Company?

E15, p.652 (see also PT 1944, p.174 and PT 1949, p.121): "A word on the Youthful Worthies as to the witness of the Spirit. Not being sons of God yet, they, of course, are not by the witness of the Spirit, the Truth, given proof that their standing is one of sons, new creatures. Hence they do not now get, by the witness of the Spirit, the same as the Little Flock and the Great Company get. They get the same witness of the Spirit as the Ancient Worthies got, i.e., that they are friends and servants and prospective sons of God. Hence, whatever in the seven witnesses of the Spirit given sons is applicable to friends and servants and prospective sons of God, is given to them. Hence as the Ancient Worthies got all of the Truth due in their days, so the Youthful Worthies get all the Truth due in our day. Hence it is their privilege as they are loyal to get all the Truth that is due the Little Flock and Great Company, dependent on whether they mingle with the Little Flock or with the Great Company. The facts of experience show this to be true. Some object that not being Spirit-begotten, they cannot see the deep things. To this we answer, the Scriptures teach for all times that the due Truth is for all the consecrated. Hence, in the Old Testament times the Ancient Worthies got all of the Truth due in their times. In the next Age, without Spirit-begettal, the Ancient and Youthful Worthies and the restitution class will come to understand everything in the Bible (Is. 11: 9; 29: 18, 24; 35: 5; 40: 5; Jer. 31: 34). Why? Because it is always the privilege of the consecrated to see the Truth due in their times. St. Paul's words in 1 Cor. 2: 5-16 denying that the unbegotten of the Spirit are able to understand the deep things are limited to the time of the general call, during which to be Spirit-begotten and to be consecrated meant the same thing, hence all the consecrated were then Spirit-begotten, which was not the case before the call to the high calling opened. Hence, after the general call ceased St. Paul's pertinent words do not apply universally. But the rule that applies always is that only the consecrated can see the due Truth. Therefore, the Youthful Worthies do have as a witness of their being friends and servants and prospective sons of God, the due Truth on the deep things."

According to these references, there were no Youthful Worthies from 1878 to 1881 since all of the consecrated were Spirit-begotten up until the general call ceased.