Do you not realise that an infinite set can be added to without the previous set thereby probed to have been not infinite..
The set of every third natural number is infinite. If I add the numbers 2, 5 and 8 to that set, it is does not make the set of every third natural number less than infinite.
Hence an infinite God can learn new things.
Paul the apostle prayed by the Holy Spirit that we would know the height, breadth, length and depth of God's love.
Although I cannot discover all the depths of God, I can know some of His depths.
I can also know some of the limits of the Almighty. He cannot lie, for instance. You surely do not think Zophar the Naaathite, whose speech God condemned, was being inspired by the Holy Spirit to speak truth in Job. 11 !!!
Thus, an all knowing God can know the number of hairs on your head because that is a number to be known. An all knowing God can know the thoughts of one's heart because that is knowledge to be known. An all knowing God can know a word in your mind before your speak it, because that is knowledge to be known.