You do not need to know everything before converting.
Once you believe that there is only ONE True God to be worshiped (Allah), and that Muhammad pbuh is his last prophet and messenger, and agree that Islam is the true religion of God, then you should accept Islam and not delay it. You will continue to learn more of the other things, and in more depth after accepting Islam.
During the earliest stages of Islam, people would accept Islam after discovering its truth, and afterwards, began learning the prayers and reforming their lives. You are not expected to know everything about everything before accepting Islam. As long as you believe in the six articles of faith, this is sufficient. This is the moment you know that you are ready to recite the testimony of faith called the shahada.
None of us know when we may die. Death can come at any time, without notice, and we do not want to be in a state of disbelief at that time, because it will be too late to seek the protection of Allah or his forgiveness. So the most important thing in this case would be to accept Islam without further delay.
Read about the: