chosen before the creation of the world

In him we were also chosen, having been predestined according to the plan of him who works out everything in conformity with the purpose of his will, in order that we, who were the first to hope in Christ, might be for the praise of his glory. - Ephesians 1:11-12


i've started reading Ephesians and when I came across this verse my first thought was what was it that brought Paul to this conclusion. duh...the Holy Spirit. next question. according to Eph 1:4 and 5, we were chosen before the creation of the world - For he chose us in him before the creation of the world to be holy and blameless in his sight. In love he predestined us to be adopted as his sons through Jesus Christ, in accordance with his pleasure and will. so in light of this scripture, how does that work with these verses:
"For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. For God did not send his Son into the world to condemn the world, but to save the world through him. Whoever believes in him is not condemned, but whoever does not believe stands condemned already because he has not believed in the name of God's one and only Son".

now i know this has been discussed many many times by other people but it just makes me wonder how the two work together. if we were predestined to believe, where does our free will come into play? the will God gives us to make our own choices. maybe it is God's desire for all men to come to him and thus all were predestined in that way, but still had the ability to choose to follow God or not to follow. so maybe "the door" is always open, we just have to choose to go through it.

some would argue that pharaoh and judas were predestined to make the choices they made. cuz the bible says that Judas' betryal of Jesus was to fullfill scripture. so he was predestined to betray Him and if you look at John 31:18 Jesus says that he knows those he has chosen. in terms of the pharaoh and his choices, i feel that he had opportunity to do the right thing and let the Isrealites go, but he chose not. when the pharaoh saw that his magicians could use their arts to do similar things as moses, his heart became hardened - But the Egyptian magicians did the same things by their secret arts, and Pharaoh's heart became hard; he would not listen to Moses and Aaron, just as the LORD had said. Instead, he turned and went into his palace, and did not take even this to heart. - Exodus 7:22-23. when i see this, i think he could've chosen to let them go, but he didn't. God knew that that's what would happen and then he hardened pharaoh's heart. this causes me to think that romans 1:18-21 can be applied to pharaoh - The wrath of God is being revealed from heaven against all the godlessness and wickedness of men who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God's invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that men are without excuse. also, if we read the rest of the chapter we see that God will give people over to their sinful desires. so in this way, i think that it may not have been that God just hardened pharoah's heart but that He knew that pharoah would be stubborn and refuse to believe in moses' God and he gave pharaoh over to his own selfishness and stubborness.

i think i've kinda gone on a small tagent, but anyway, i just found that the predestination subject was interesting. i've heard bits and pieces of different arguments regarding predesitination and have always wanted to avoid getting involved, and i still do, lol, but i can see why it would be a hot topic.