I believe you are both wrong, if the playing field is 100 yards long and each goal line is at least six inch long that adds additional foot to the field.
The Endzone begin after the goal line. Therefore you must cross it to score.
The white goal line is in the endzone.
Don't care what you believe, the rule is the rule. Any part of the ball touching any part of the line is a TD. (Or a safety, coming out the other way.)
Why "believe" when you can know for certain?
Since you don't believe the football fans on this forum, will you believe the NFL rulebook?
1. Sidelines and end lines are out of bounds. The goal line is actually in the end zone. A player with the ball in his possession scores a touchdown when the ball is on, above, or over the goal line.
SD
No, the technical zone of the boundary for all boundary lines on the field (goal line and sidlelines) are defined as the interior edge. So one micron of the ball over the white paint of the goalline is a TD, and one micron of a shoe on (remeber you're not out of bounds until you touch) the white paint of the sideline is out of bounds.