I believe “this age” is the one we live in presently and that the “next” is “eternity”, there is nothing beyond eternity. This means to me it will Never be forgiven not now, not at the white throne judgement, and certainly not after that. Though I dont think it is possible to unknowingly commit Blasphemy of the Holy Spirit. If one is a true christian they will never fall for good, they will return. It can take years for some to come to serve the Lord with a true commitment. Others may stray a few times before truly being sealed by the Spirit or staying dedicated to Him. But I definetely believe that blasphemy of the Holy Spirit is Unforgivable.