What is prevenient grace? It might be defined differently by Calvinists, Arminians, and non-Cal/Arms.
I use the term to refer to a supposed grace whereby God enables, but does not compel people to receive and understand the gospel. The idea being that a natural man, i.e man of flesh (in a fallen state) is not able to respond appropriately to the gospel. In my opinion it is false doctrine.
Now revealing grace must come before a person could trust in that revelation, but I believe scripture teaches fallen men are able to understand that revealing grace, the milk of the gospel.
As far as the Calvinist take, the prevenient grace is irresistible, that too is false doctrine.
I Corinthians 2:14-3:3 teaches men of flesh, i.e. not babes in Christ or spiritually mature Christians, can understand the milk of the gospel, but not other spiritual things discerned only with the aid of our indwelt Spirit.
And I believe Matthew 23:13 teaches men can be entering heaven, thus able to enter, yet be turned aside, thus the enabling is resistible.
In summary, my view of "prevenient grace" is the revealing grace of God which is necessary in order to have something in mind to trust in. But it does not supernatually alter (enable) a man of flesh to respond, they are able to respond in their fallen state. Thus regeneration does not come before faith.