Is it realistic? No. Getting a 9-5 and saving etc is realistic. Poker is not.
Is it possible? YES! Don't let the odds
scare you. It is definately possible.
Yes poker is becoming harder and more popular etc, but it's also turning alot more players every year into fulltime players.
Cash games are the best way to make a living, this is well known. The variance in tournaments is incredibly high, and other then the TV pro's that you love to watch, most full time players make their money off of cash games.
I can't stress this enough: Do not think you can sit down and be a pro... Be prepared to dedicate years of your life to this. So keep a fulltime job as well as poker on the side, and go fulltime when you're ready.
You have a 3k bankroll. That's heaps for online stakes, but even for $1/$2 stakes (Usually the lowest a live poker room offers), that's not enough, it's only 15 buy ins. You can go through this in a week if you're not careful.
IF you want to play live, save about $10k. That's enough to get going for $1/$2 and even $2/$3. This however is NOT the case for online. The general rule of thumb for online is you want "100 buy ins" of the stakes youre playing.
You can be a bit more lenient when playing live, generally if it's less then %5 of your bankroll, you can afford to play those stakes.