What is free will? Is God free to do only good, can He do evil? If He cannot do evil, how can He be truly free? If God does not have free will, how can we expect to have it? God’s desires are for the good, and had our first parents followed His law, so would ours. But, as the Exsultet has it:
O happy fault,

O necessary sin of Adam,

which gained for us so great a Redeemer!

For though we were utterly lost, and although we deserved only the punishment for our crimes prescribed in the Law, God sent His only-begotten Son that we should live.
Before we were made, God knew us and our fate. But that does not mean that we are robots programmed by God. We have the power, which, alas we frequently exercise, to reject Him. Made in the image of God, we are limited by our fallen nature. In telling us that God is our Father, Jesus tells us much. God wants our love
Since the Bible clearly teaches us that the unbeliever is restricted to making sinful choices (1 Cor. 2:14; Rom. 3:10-12; Rom. 6:14-20), we must conclude that anyone who believes in God (John 3:16; 3:36) does so because God has granted that he believe (Phil. 1:29), has caused him to be born again (1 Pet. 1:3), and chosen him for salvation (2 Thess. 2:13). But does that mean that the moment we receive Him, we are sinless? Does it mean we cease from sinning? No.
Nice though it would be were that the case, we retain our free will. There is some dispute in Calvinist circles about ‘irresistible Grace’, with some holding that although Grace is offered to all, only the ‘elect’ will receive it, and they have no choice. What puzzles me in all such disputes is that no one turns to see what the Fathers have written. St Cyril of Alexandria, whose commentary on John repays the effort of reading, has quite a few things to say about this: 

‘But having said above, No man can come to Me, except the Father Which sent Me draw him,He shows that it is not a compulsory nor forcible drawing, adding, Every man that hath heard of My Father and hath learned, cometh unto Me.

For where there is hearing and learning and the benefit of instruction, there is faith, to wit by persuasion and not of necessity: and the knowledge of Christ is given by the Father to them that are worthy, helpful as of love, rather than constraining. For the word of doctrine requires that free-will and free choice be preserved to the soul of man, in order that it may ask the just rewards of its good deeds, and if it have fallen from right, and from heedlessness have transgressed the Will of the Lawgiver, it may receive the doom of its transgression and that most reasonable. (Commentary of the Gospel of John, Bk. IV, Chap. 1)’
‘He says that He so kept His disciples, and had such care for them, that none of them was lost save one, whom He called the son of perdition; as though he were doomed to destruction of his own choice, or rather his own wickedness and impiety. For it is inconceivable that the traitor disciple was by a Divine and irresistible decree entangled, as it were, in the snare of the fowler, and brought within the devil’s noose; for then would he surely have been guiltless when he succumbed to the verdict of heaven. For who shall oppose the decree of God? And now he is condemned and accursed, and it would have been better for him if he had never been born. And why? Surely the wretched man met his doom as a consequence of his own volitions, and is not convicted by destiny. He that was so enamored of destruction may well be called a son of perdition, inasmuch as he merited ruin and corruption, and ever awaits the day of perdition as fraught with anguish and lamentation. (Commentary on the Gospel of John, Bk. XI, Chap. 9)’
St John of Damascus is also a font of good sense on this matter:
‘We must recognize that while God foreknows all things, He does not predestine all things. He foreknows the things that depend upon us, but He does not predestine those things. He does not will the doing of evil, nor does He compel virtue. (The Fount of Knowledge, Bk. III: 2,30)’
‘God Himself has given us the power of doing good. And He made us self-determining so that the good might be produced both from Himself and from us. Whenever a choice is made that prefers the good, God is cooperating in the good in such a way that we do thing that are, while consistent with our nature, yet above our nature. (The Two Wills in Christ, 19)’
God’s Grace does not take away our free will and force us to do something He wants; were that so, he could force us all, and there would have been no need of the Incarnation. No, God’s grace helps us to fulfill His commandments. Adam knew grace but he could still exercise his will. As it was with the old Adam, so it is for those saved by the Second Adam.