I didn't jump right into the touring thing ... I sort of eased into it.
I guess my first sort of tour was in my first year of "serious" cycling in 1990. My father and I cycled a 50 mile U shaped route in northern Alberta, and my husband at the time met me in a town at the end of the route, and we camped overnight. It was my intention to ride home the next day, but the next day was a horrible day for weather so we just drove home. But the day my father and I rode was one of the hottest days of summer.
Then I suppose the next might be a 4-day adventure in 1995. My father had ridden Jasper to Banff in three days when I was 17, and I rode the last day with him. When I did that, I told myself that one day I'd do the whole thing myself. So in 1995, I did. Two days of riding, a day off, and then the third day to finish. That was a supported tour because my husband at the time sagged for me. The weather was typical of summer in the Rockies ... cool and rainy with some warm spells.
And then I think it was in 1997 when I rode a MS150 event ... cycled from Winnipeg to Gimli, stayed overnight, and cycled home the next day. Fully supported, of course. I enjoyed that ride, and the next year I got into racing because of some of the people I met on that ride. Weather? Seems to me that Day 1 was very, very windy, but Day 2 was nice.
Then I got into racing for the next three years ... and then into Randonneuring ... and then Randonneuring led back into touring again as well as into other long distance riding. I've written about the more recent tours etc. here:
http://www.machka.net/
The thing is, the more you cycle, the easier it is to ride long distance and be comfortable on the bicycle. You also learn what you need to bring in terms of clothing, tools, food, etc. etc. I'm talking about cycling in general ... not specifically touring. Prior to, and in between, the short tours I mentioned there, I rode my bicycle regularly ... commuting to and from work in all sorts of weather, doing centuries, exploring my local area, etc. You've got to get out there and ride lots. Experiment with stuff ... do short tours to practice with your panniers, and other touring gear. Do long rides that aren't tours. Ride as many days in a week as possible so that you get a feel for getting on your bicycle day after day.