Guys do you think this game would be good for a 12 year old girl who likes playing games like the sims 4 ?
Also will a i7-4770k with a 3GB GTX 780ti be enough to run it ok at 1440p at say med detail settings ?
As mentioned, once the zoo gets busy it can bring a system to it's knees. For reference, my wife has a 2070 Super, 8700k (at stock, no OC) with 32gb ram. At 1440p it runs fine at ultra. However, with the spec you mentioned, I'd imagine it's gonna have to sit at low/medium at 1080p to play smoothly.
However, for a young child, I doubt they will really care too much about performance/graphics so you might be good to go.
As for if it would be good for her, absolutely! It's very easy to pickup, super informative and really awesome with all the animal interactions.