Are you serious? The Zepplin was invented in the 20th century, and not even gunpowder has been invented yet, so the Zepplin is most likely NEVER going to show up.
EVER.
Prerequisites: Mid-High Tier Metallurgy (6?), Chemistry or Electricity, Mid-level Mechanics (5, likely).
Dirigibles aren't that difficult in terms of the physics - they're essentially metal balloons full of hydrogen or helium. The principal engineering difficulties are the machining problems (the parts require a fairly developed level of machine tools, but not even as high as required for rifles), materials (reasonably high level metallurgy should take care of that, though - various types of steel work fine) and controlling the direction. Whilst by the time Dirigibles came about on Earth self-powered engines were well into production, there is not that much to prevent sails acting to control direction and provide propulsion in this setting.
The main chemical challenge is producing large amounts of hydrogen. Electrolysing water is one of the cheapest, most efficient ways, but there are plenty of other means of producing hydrogen for dirigibles that are available without knowledge of electricity.
And yes, as a matter of aid for the others when you do PM me a turn be sure to post here that you've done it. Helps me make sure I've got everyone's turns together when I flip through the thread.
I'll start doing turns tonight, but I'm pretty busy at the moment. Got one of my last drama school auditions the day after tomorrow and the one I had today was sadly unsuccessful (as so many more of them have been =/). Will be preparing for that.