When do you class change does your proficiencies stay or do you go back down to zero?
ex: barb has 5 proficiencie in axe if he switches to sam will they still be there?

Nope, everything stays. Proficiencies, kills, deaths, starting stats, etc.

Just reroll and change class

Thank you very much because i was giong with a barb then i wanted to make a sam later but i started on axe and i though of it after i hit 20