You can do whatever you want and apply what's usefull for you
If you want to learn how to do acrobatics find a qualified gymnastic coach and it will certainly help you out. If you want to learn martial arts and/or selfdefence starting out with, for example, krav maga will help you out with that. If you wish to increase your coordination and general bodyawareness and become more flexible starting ballet will certainly help you with that. Same with parkour or freerunning. If you want to learn more about it find a qualified coach, or any others person or group with knowledge and experience. Is it required? No. You can learn acrobatics on your own, you can learn self defence on your own, you can learn freerunning on your own, but it will be away more timeconsuming to do it on your own since it is required that you do a proper research and study it very closely.
Personally, I had no previous experience in any sport at all
before I started training and practising parkour. I used the internet for tutorials on movements, and I used the internet to research about almost every tiny bit about parkour and freerunning. Nutrition, warmup, stretching, history, training method, philosophy, inviduals.. there is huge amounts of information available on the internet. The hard thing [as bruce lee said] is to absorb what is usefull and reject whats not...
All this depends on your goals. Do you want to learn freerunning? acrobatics? Tricking? martial arts? ballet? Do you want to incoporate all of it?
Just do what you have to do.
So I think the answer to your question is in the question: If you wish to learn flips and tumbling it will be more efficient (!!!) to start training gymnastics. If you wish to learn parkour/freerunning it will be more efficient and usefull for you to start of with that. If you wish to learn selfdefence krav maga will be efficient for that. All in all, all these things will give you a certain understanding and aid to one and each others
in different ways.
So do what you have to do!