As I can see you have already completed some of the levels, you can carry on completing levels and if you are stuck you can post on the forums for help.
Look at this site: http://xeushack.com/index
Learn HTML and Javascript it will help you understand webpages better.
Hope you enjoy your stay here. :)
@tanyuanjin Age is no issue. One user on hackquest (now defunct :( ) became an admin at the age of 15 and had all challenges solved at the age of 14 - he was probably the best admin the site ever had too :)