This is a somewhat complicated question. First of all, God cannot reveal all knowledge to us. If he did, then the Bible would be trillions of pages long. There is an infinite amount of knowledge that God does not reveal to us. I assume that he reveals to us the things that it is essential that we know. In fact, if you go to the Garden of Eden, you will find that there was some knowledge that God did not want Adam and Eve to have. I assume that such knowledge was not helpful for them. In fact, this knowledge was extremely harmful to them. When they foolishly and rebelliously chose to eat the forbidden fruit, they gained such knowledge, and this led to their fall and removal from the Garden of Eden.
From this story, we know that there is knowledge that God has which is not helpful for us, and even some knowledge which is harmful for us. As a parent, I understand this concept well. There are truths about the world that I very carefully hid from my children when they were small. Was this because I was selfishly keeping this knowledge to myself so I could have an advantage over my children? Not at all!!! Like Jack Nicholson said in the movie “A Few Good Men,” sometimes we cannot handle the truth. Sometimes God conceals things from us which are true, but which it would be harmful for us to know these things.
By the way, this may be a bit of a non sequitur. In other words, the example I took from the Garden of Eden may not apply to what Jesus said in Matthew 11:25-27. It may be that the things God hid from the “wise and learned” but revealed to the “little children” was not inherently harmful at all. Maybe this knowledge is something the worldly and prideful would use for destructive purposes. To give such knowledge to the prideful would be to “throw pearls to swine.” I do not know. Nevertheless the general rule applies, which is that God loves us and what he chooses to reveal to us or not, he does so because he loves us. In the particular case of Matthew 11:25-27, God reveals himself to those who are humble and open, not to the prideful and arrogant. Exactly what is this knowledge? I do not know, and I do not need to know. What I know is that when God reveals something to us it is for our good and when he withholds information from us, it is also for our good. We need to trust God on this kind of thing.
How do you know whether or not the Son has chosen to allow you to know the Father and to reveal him to you? Let me suggest this. What you should do is you should read the Scripture. You should apply both your mind and your heart to understand the Scripture and to put it into practice with all your heart. The more humble you are and the more you submit your will to God, then the more he will reveal to you. I believe that this revelation will come primarily from the Scripture–the Bible. This is the chief means of our gaining knowledge of God. But, God can also speak to us through the Holy Spirit who lives in us if we have been baptized into Christ. So, whether God is giving knowledge to you through your study of the Bible or some sort of individual understanding he gives you through some other means, you should leave that to God. Trust him. That is the key. Do not be like Adam and Eve and demanded God give them knowledge he did not want them to have. Trust him and let him work in you. Do not seek special knowledge but seek to love and to serve God and let Him decide what to gift you with.
By the way, what I am saying here is biblical. In Deuteronomy 29:29 we find that there are “secret things” which belong to God, but that the things he has revealed to us are things which are helpful so that we may obey God. We should not seek to uncover this hidden knowledge. This would be presumptuous and show contempt for God who gives us what we need.