I might be misunderstanding you, but I'll give this a shot. The son is not second and the Holy Spirit is not third, if you are speaking of their timeless existence. Words (order) like this only have meaning in a context which has time as a factor. Both the Son and the Holy Spirit are supposedly "co-eternal" with the Father. The son is begotten by the Father, and the Holy Spirit proceeds from the Father, as an actual state of existence, and not as a set of relational actions which was one time not present, and then afterwards came into existence.