The ground fighting styles are all more practical for actual professional fighting.
For choreographed movie fighting, Tae Kwon Do and Kung Fu are good choices.
But in real life, almost all fights go to the ground in the first few seconds.
How long it takes to "master" the skill is pretty subjective, and varies from person to person, but a pretty good rule of thumb is you'll be able to impress your friends after a year, you'll be genuinely good after five, and you'll be great after ten.
Try Muay Thai or kickboxing. If your really dedicated it might not take that long, but most of the time it will take a while.
mantis style kung fu. its deadly. it takes a lifetime to master but even when you are old and sickly you will be able to beat anyone easily and soundly with a single blow.
I'm a 16 year old female and I'm looking to take up professional fighting. Which style involves kicks and punches, standing up, not fighting on the ground, and is more "aggressive". I want to focus on releasing energy not relaxation. Something kind of like what you see in assassin or action movies. And how long would it take to master the skill? Thanks!