Actually you are wrong. Paul was among the first to mention dispensations of time.
1Co_9:17 For if I do this thing willingly, I have a reward: but if against my will, a dispensation of the gospel is committed unto me.
Eph_1:10 That in the dispensation of the fulness of times he might gather together in one all things in Christ, both which are in heaven, and which are on earth; even in him:
Eph_3:2 If ye have heard of the dispensation of the grace of God which is given me to you-ward:
Col_1:25 Whereof I am made a minister, according to the dispensation of God which is given to me for you, to fulfil the word of God;
Eph 3:1 For this cause I Paul, the prisoner of Jesus Christ for you Gentiles,
Eph 3:2 If ye have heard of the dispensation of the grace of God which is given me to you-ward:
Eph 3:3 How that by revelation he made known unto me the mystery; (as I wrote afore in few words,
Eph 3:4 Whereby, when ye read, ye may understand my knowledge in the mystery of Christ)
Eph 3:5 Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit;
Eph 3:6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel:
MB