When you form a relationship, how much are you ever willing to share? Do you want to share everything, or do you feel you must always hold something back? (see below)
No, you do not want to reveal everything at first. You do need to make yoursef vulnerable by sharing somethings of significance about yourself, but also need to wait to see if the other person (1) is willing to reciprocate, and (2) will not betray your confidence or try to use what you have revealed against you. If the other acts with honor and affection, it is time to open up further.