Doesn't that sort of depend on what kind of tools are at your disposal, how long your game is going to be, what kind of features you're going to add, etc?
I'm sure a decent 3 hour game using the RTP, an ABS, a couple in-game features like crafting and cooking and mining, along with a nice collection of maps and quests would hardly take more than a year. Even a month, if you already have an idea and are willing to put in 2-3 hours a day. RM game contests typically go 2-3 months and the games that come out are usually pretty nice.
All that time saved from having to draw your own art, developing your own engine, writing your own features, ...
Lots of doujin games are released every few months and some groups are pushing out games regularly at every convention, and some of them record their development from start to end on their blogs and it usually isn't "years to make".
Plus OP says he doesn't have a lot of time left, so if he wants to fulfill his life by making a game, why not LOL