I dont want to rain on your parade or anything but you will not be able to make a game like Runescape. That's a MMORPG and takes years for big teams to develop
You're better off with doing stuff like Pong, Pacman and maybe even a platformer when you're ready? Just increase the difficulty of the game after every finished project and you'll be fine
There's lot of RPG's made by one guy, and they're better than Runescape...how come I can't do it? With work and dedication I'll do it and I know it'll take years.
Well, you said you wanted to make a game like RS, and RS is a MMORPG, which is a HUGE game. Seeing as it takes years for a big team of professionals to make a MMORPG it will take a single beginner lots and lots of years. If you really want to do it you will probably be able to do it but since it will take so many years there is a high chance of you not completing it.
I'm not trying to be a douche, just being realistic.
EDIT: There is lots of different RPG's, maybe try making a text-based?