I would suggest that you might wish to start by fooling-around with BGE. Seriously. The first thing that you need to grok is “how games basically work.” Within the Blender environment, and without leaving that environment, you can produce assets and turn them into a serviceable game.
Also, spend a lot of time in the “Games” related forum-sections here … when someone posts a game, grab it, and reverse-engineer it. (In other words, “figure out how the damn thing works!” :yes: ). It is always easier to study something that exists, and that is working. Why not now rip the guts out of the thing and, say, replace all the images?
When you move on to “real games,” there are many technologies and frameworks that you might use. Apple is doing many interesting things with its new Swift language, and I have spent a lot of time with the cross-platform OpenFL and Haxe languages.
But, once again, there is this cardinal rule:
Actum Ne Agas:
Do Not Do A Thing Already Done.
You (almost) always build your “new” game using some kind of framework that, though it does not do all of the work for you, does do everything possible that is “common to ‘a game.’” Every “thing already done” is done by the framework, and, in the open-source tradition, if you extend the framework in a new and useful way in the process of developing your game, you are obliged to “give back” to the framework.
All of the languages aforementioned have multiple game-frameworks. (BGE, itself, is a framework of sorts, although it is tied to Blender.) By identifying common game features and cooperatively pouring development-effort into it, “a rising tide lifts all boats.” 80% of the source-code in a game might be common to all games … (“been there, :ba:ed that”) … and it is the 20% that makes the difference.
Beyond that, my friend, “it’s time for swimming lessons.” Study the book on swimming, reverse-engineer existing work, then … it’s time to get into the water. (Stick to the shallow end, and wear your life vest, and tell someone else where you’re going in case all they see floating on the surface is your hat, but: get in.)
A famous-to-me developer, “David-I” of Borland International, used to write a regular column called, “A Sip from the Firehose.” You should expect a fire-hose experience. Keep a pencil-and-paper journal by your side and write down everything that slaps you in the face so that you can deal with it at your convenience. The waters of that swimming pool will be confusing, but only at first.
Enjoy!