Once you have a firm spiritual, social, financial, and intellectual foundation, you are ready to begin your martial arts training. That being said, there is one important thing which you need to understand before you start. The most essential element of your martial arts training is not your athletic ability, your style, or your master.
The most essential element of your martial arts training is YOU!
Your determination, your heart, and your fighting spirit will determine whether or not you will succeed in your martial arts journey. You can have a potbelly and study Angry Bob's Couch Potato Drunken Fist under Sensei Moron, but if you are truly determined to become a warrior, you will succeed. Likewise, you can have an Olympian physique, have a membership to Greg Jackson's gym, and train under Bruce Lee's best successors. However, if you don't have the passion or the drive, you won't be able to fight your way out of a petting zoo.
Katas, drills, mat time, and sparring don't create martial artists. They reveal them. Whether or not you become a martial artist is decided before you step into the dojo. And the person who makes that decision is you.
If your heart isn't in it, you won't make it past white belt. If you are wishy-washy, you won't make it past the intermediate ranks. You will only become a black belt if you are truly determined and put your heart and soul into it. To survive, much less thrive, in the shark tank known as the advanced black belt ranks, you will have to make an even deeper commitment.
If you are truly committed to becoming a martial artist, then nothing will stop you from achieving your goal. If you are not, all of the talent and instruction in the world won't help you, so you may as well stay home.