A friend sent me and some other friends a message on facebook the other day asking about how much of our past - our past as in before being a Christian - should we share. She had a conversation with fellow believer about "does deep or graphic testimony encourage non-believers or fence-riders to engage in or continue to engage in sinful behavior by reinforcing the fact that our Father forgives even the worst of us?" ( The sitting being in private or church Bible study/fellowship, etc.)
I think the simple answer is yes and no.
The real question is the Holy Spirit saying? There are some seekers/new believers that need to know that God really did forgive you for this behavior and that sin. And not only did He forgave you, but you have moved on into a deeper relationship with the Lord.
But there are some that will see that sin in your past life and that's all they will see. Another friend once shared how she shared once that she use to cuss a lot. One lady continually brought it up as time went on. It was like she could now only see my friend as how she was in the past - not what and where God had brought her to now.
I am convinced that we women share too much too soon. I have been amazed over the years at how personal the conversation can quickly become with women! We need to guard our hearts.
Last week in Bible study we studied Hezekiah when he showed the Babylonians all that he had. He was so flattered that this new & up-in-coming world power was interested in him, that he throw away common sense and showed them all his treasures as well as what was in the temple - military items as well. We, too, shouldn't let "flattery" (attention, friendship, etc) get the best of us.
This is where praying without ceasing comes in - if we have that consistent, open communication with the Lord, the Holy Spirit will give us the words that need to be said at that moment.
I don't think at all we should ever lie or cover-up what we use to be, but I do think there is a time & a place for to share our past sins.