How old were you when you started and who's clothes?
I first wore my mom's clothes at around age 7 or 8 and sporadically since. When i married, i swore off CDing but within the first year, i begged my wife to let me wear her clothes.
She allows me to wear her clothes, but i now have to give her a bigger clothes budget :) Suits me fine.
Unusual start to dressing
I have been reading this thread and I think I can say mine is the most unusual start to dressing. At least in where I found my clothes. In my teens mum and dad ran a small hotel. Now you would be amazed at the things that people leave behind when they check out, Men tend to leave socks and ties. Women leave cosmetics by the box load. They also leave behind a mountain of clothes including underwear. We used to hold on to most items for a while to see if the guests would claim them when they found them missing. Very few did. We stored them in a large box and after a decent interval we would take them to the local charity shop. It was my job to sort out the clothes for disposal. Needless to say by the time I was sixteen I had a very extensive collection of female underwear. The rest as they say is history