I'm currently in a 3.5/pathfinder campaign. (Mostly 3.5, but since it's steampunk we're borrowing liberally from pathfinder as we find the need.) We started as commoners, the idea being that we would gain base classes as we began to act like heroes, and as circumstances warranted. Our fighter killed a wyrmling, gaining his levels. The rogue seems to have acquired his from an artifact of some kind (He's being a bit cagey, but keeps making a point to sneak before beginning a fight.) The rule somebody remembered (and nobody challenged) was that if a commoner advanced to a base class, you replaced all previous levels with levels of your new class. It made more sense than multiclassing, and fit with the notion of warriors becoming fighters and suchlike. I can't find anything in the core book that speaks to the issue, so that's part of my question- what actually happens when a commoner advances to a base class?
But the important part, the previous question being merely a prerequisite, (whatever the ruling, we aren't changing how we do that now) is what happens if a commoner tries to advance straight to a prestige class? I just noticed that Shadowdancer, which would fit my character just fine, just has skill and feat prerequisites. I'm an int based human, that's pretty easy. Can I just jump straight into a prestige class from commoner?