In reply to butterfingerz:
Start now! take an indoor leading course to start off with. your local climbing wall may offer something and there should be plenty to lead within your grade there. once you get used to leading find some very easy outdoor stuff and learn the trade and build experience. I wish i didnt wait so long to go outside. i told myself i wanted to be a 7a climber before doing trad climbing. well i would have missed out on some of the greatest times of my life because 3 years on i still havent climbed that grade
Outdoors climbing is so different to indoor. learning to search for holds, placing your own draws, anchors, absailing/low off, bigger falls, climbing further above gear. longer routes, trad adds placing gear, building belays and even more ropework skills as well as general outdoor skills.
I actually prefer Trad as i am finding more interesting climbs throughout the lower grades where i climb. for example this climb is lower than a 5+ sports climb (although there is a lot more to it than just a grade).
http://www.ukclimbing.com/logbook/c.php?i=3254
the only trouble is climbing indoors exclusively with sports climbers+boulderers for the last 3 years i think most of this is lost on my mates as its not fun or a challenge to them to climb to me what seems like an adventure.
also just to repeat monks recommendation:
TradClimbing+ is a fantastic book
lastly when you get outside you find you can learn new techniques that aren't always replicated or present in the indoor setting. this will make you better all round climber