The position of the first author has never been an issue. It's always reserved for the individual who wrote the paper and did significant experiments with respect to the article.
The issue has always been on the second author and the third/ last author (where there are more than 3 authors). Does the positioning really matters? In case of a student with two supervisors, between the first and the second supervisor who should be the second and who should be the third author? Does the second author have any advantage against the third or vice-versa?
Kind regards.