Sin was in the world before the law came, but sin is not counted against anyone where there is no law.
In context
11And not only that: we boast in God through our Lord Jesus Christ, through whom we have now received the reconciliation. 12So then: through one man sin came into the world, and death came in through sin, and in this way death spread to every human being, because everyone sinned. 13Sin was in the world before the law came, but sin is not counted against anyone where there is no law. 14Yet death reigned from Adam to Moses, even over those whose sin was not like Adam’s breaking of a command. And Adam is a pattern of the one who was to come. 15But the gift is not like the trespass. If the many died by the trespass of one man, how much more did God’s grace, and the gift that came by the grace of the one man Jesus Christ, overflow to the many.