100% absolutely guaranteed. I don't know how to give a stronger oath. I have a spreadsheet, and keep track of everything. I have two buddies I told when it happened, other than that, not sure what else to say. I track my game shape/DMI/and Eperience each week.
Now by contrast, I have another player who has played just as much, and in the same games, and he is still at 1 experience. So it's all weird to me.