The Lancaster Covered Bridge ride was my first event when I started cycling in 2002 (started in May). I did the full metric century distance on a hybrid bike. One month later I sold my hybrid to my neighbor and bought a road bike. The reason being was that I found that I loved the longer rides and the hybrid was do-able but not the appropriate bike for what I enjoyed. Putting a hybrid vs. road bike discussion to the side, 17 miles might seem far to you now, but it will be a piece of cake if you enjoy cycling and get out often next year - if so, I predict that you'll end up doing at least the half metric century (50km) distance (and a hybrid would still be fine, just a bit more work). You'll also find that when doing an event the time will go by really fast. And congrats on getting out so far this winter, pretty motivated, eh?