first off i wish you luck on your endeavour.
having had some experience in the game industry i can give you a few things to think about.
depending on what type of game you want to do and how complex will determine how hard it will be for you to create it, best advice is for your first game start with something really simple just so you can learn the basics. if you are making the game all by yourself then you are going to have to learn how to program and do the graphics and sound and even though this sounds like fun does require some specialist skill and i can guarantee that it can take years to any good level in one or even each of these areas.
another thing to consider is the planning of the game, sit down a sketch out how its going to work interms of gameplay, rules, storyboarding etc.
you have some things to consider technically if its a 2d game you dont have to many problems, but 3d you have many hardware requirements to consider and this can make the development process a whole lot harder. its also important to make the game run as fast as possible so making it efficient is very important and requires you to know how to optimise code, graphics and sound clips.
there are a lot of resources on the net i would suggest starting with a site called gamasutra, it has many resources to get you started. there are also a huge number of development resource site that will help you start learning to program and get into the graphics and sound.
it may sound a bit daunting but it is a big job and if your doing it by yourself it means you have to do the jobs of a few people combined, so the best advice i can give is to search the net, learn as much as you can from game dev communities and start small, if you aim too high you will more than like fall short because you will be overwhealmed, so start with basics and progress from there. it will also take alot of time to learn everything so be prepared to put in years worth of learning and experimenting

dont expect to be creating games like doom3 straight away, commercial games have team of specialist people with many years of experience and games under their belt, youd probably be creating games like what you see on the amiga ;-P there is a huge public domain community for games so have a look there and find out how they are creating games. you could even have a look at some of the game creating engines around, that will definately give you a good idea on what is involvers technically.
hope that helps, good luck