Those Disciples in Acts 19 believed. That means they were born of the Holy Spirit. Nevertheless, they had not received the Holy Spirit. There is a difference.

The Believing and being born of the Spirit come first:

"... as many as received Him, to them He gave the right to become children of God, to those who believe in His name:

who were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God," John 1'12-13.

It is beyond doubt that those who believe are born of God, born again. Their new birth is by the Holy Spirit as John 3'6 says:

“That which is born of the flesh is flesh, and that which is born of the Spirit is spirit,".

This is the time to ask God for the Holy Spirit, as Paul indicated. Those who have not done so, are encouraged to become receivers. The promise is to all Believers.

Did you receive the Holy Spirit when you believed?