Men’s and women’s roles

Since Jesus was the ultimate sacrifice for all of our sins, and all sins have been forgiven, including Eve's sin, why is it that women still shouldn't be pastors or teach in service?

The lead-in to your question seems to imply that the inability for women to serve as pastors is a consequence of sin. That is not the case. 1 Timothy 2:11-13 and 1 Corinthians 11:8-9 make it clear that the roles God established for men and women have their origin at their creation—before the fall into sin. The roles of loving leader for men and loving helper for women are part of God’s design for people.

Jesus definitely was the ultimate sacrifice for all our sins (Hebrews 7:27). Jesus “is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world” (1 John 2:2). In gratitude to God for that forgiveness, we strive to live lives that follow his will (2 Corinthians 5:15).