Minecraft can be
extremely addictive. I know from personal experience. To give you an idea, I'm a freelancer and for a large percentage of last year I was playing more hours of MC a week than I was billing clients.
You sound like you may be similar to me with games so let me lay it out for you.
When you first start playing you know nothing. There's so much to do and learn. You'll be scared of nighttime and dark caves. You won't know how to craft anything. You'll probably get killed a lot and get lost. It will suck you in for the first 30-60 hours while you learn how to play single player.
At that point one of two things happen. Either you really like building structures and you keep playing a lot or you get bored. I got bored.
Then I realized I was only experiencing a small fraction of the game. The modding community is HUGE, larger than any other game I've played. There are hundreds of mods available that expand and modify gameplay making it far more interesting than "vanilla" MC. Each mod can add 5-50+ hours of interesting gameplay.
This isn't even accounting for multiplayer, which can be much different. PvP servers with clans, mod servers with large towns, creative servers with builds that take months to complete.
I'm not saying you shouldn't play. Minecraft is a great game. Just be aware of where it can lead if you don't plan your time well. I've since cut way back and don't play games as much.
One way you can get a good feel for MC is to watch some of the popular YouTubers. I primarily watch the Yogscast but there are plenty of other good ones.