I started in 2008 as well. At the ripe old age of 22, nearly 23.
(not sure if I look it though)
But I know about as many cosplayers in their twens (and some even older) than in their teens. Of the older ones some started very early, 7 or more years ago, some within the last 3 years not that much younger than myself.
The advantage of starting later is that it means less trouble with travelling, parental supervision and possibly a greater variety of resources.