Christians only please! What happens after death to an extremely good christian who has before marriage?

It isn't about what you've done; it's about where your faith is. Those sound like all very nice things for a Christian to do, but none of those things will "get" someone into heaven. Only faith that Christ's work alone on the cross was sufficient will do that. When someone is in Christ, their sins (including premarital ) are forgiven. Being in Christ, however involves a renewing of your mind in which you should strive to not do certain things anymore.