wow, that is an ambitious dream...

I dont know much about RuneScape, but i do know quite a bit about Java, though i am no expert. I did a search on RuneScape, and found the wikipedia page on it, which told me the following:
  1. Was originally a one-man creation - called DeviousMUD, made in 2D
  2. Became more 3D when released for net as RuneScape. Made by a team of 3, and is now maintained and extended by Jagex Ltd.

creating a game similar to this (3D graphics etc.), with no previous programming experience, will be quite a complicated and time consuming task, however, it is definately not out of reach.

now, i know you just want to get into it and start making the game and all, but i would suggest that perhaps a better place to start would be learning a programming language from the start. The language itself doesnt matter that much, but, in order to achieve your goal, you need to start with the basics - you cant just dive in and expect to be able to program with 3D graphics.

i started programming with BASIC (and variations of it) and then Java, which i enjoy a lot. imo Java is very useful, and is a good language to learn - not that much more difficult than BASIC and with greater capabilities...

i dont actually know if you could create a game like RuneScape in BASIC, but as i said before, all that matters is that you start with the basics of programming, otherwise, you might not get very far...

still, i encourage you in your ambition.