The summers of 2001, 2002 & 2003, I noodled around on a mountain bike on paved flat trails, just a little. No more than about 1/2-weeks, and no more than about 10-15 miles at a time, TOPS.

Spring of 2004 I did a few rides on that mountain bike of up to 30 miles on paved, flat paths. Then, in August 2004, got my first road bike and did severals firsts all in one week:

* First multi-day tour (6 days, 500 miles, 20,000+ feet climbing)
* The first three days of that tour were personal bests (60, 65, 70 miles)
* That was also my first organized ride
* That was my first time riding in 100+ degree heat

I LOVED IT!!!

I barely rode the following fall and winter, and did a lot of 12 mile rides all spring, with a few 60 milers, and one 70 miler. That July I did my first century (100 miles). I did the Seattle to Portland ride (100 miles on both Saturday and Sunday). I did it alone (another first). I did day #1 in 8 hours (and I had never gotten to sleep the night before, not once!). The second day was wet and rainy, and I took 10 hours.

I was not fast, but it went GREAT, and was a huge confidence boost.

Go for it!