Go for it! You'll hook up with someone to ride with. I did do a fairly new (second year for it) century ride last year -- less than 1000 people participated and I did ride alone a lot. The larger rides are better I think if you are going to do it without a partner. Make sure you have a map and don't lose it! My bike shop was happy to have me watch them change flats -- and gave me tips. I would practice at home - maybe while watching tv.

Keep us posted.