If you want to be a "certified" dog trainer, all you have to do is become certified through one of the many programs out there.
If you want to be an effective dog trainer, you really need to train a bunch of dogs. Living with dogs is part of that. My dogs all have an "actively training self" and a "not actively training self." People need to be able to deal with both mindsets and they are really different.
When actively training, it isn't important to think about exercise, management, enrichment, nutrition... When living with a dog, these things become critical. These issues are critical to the owners you'll be working with.
I would live in my van with my dogs before I would live in a petless mansion. In college, I lived in some really terrible places in order to keep my dog. I can't imagine spending one minute or one dollar to train with someone who wasn't equally passionate about dogs. Dog training has some real challenges to it. Without a strong passion for dogs, I can't imagine how one could stand to do it. Given the language aspiringdogtrainer is using to convey his/her dog experience, it's very hard for me to imagine that this is a "best choice" for a career path. I would suggest getting into the world of dogs as a participant before trying to be a professional.
I am a mentor trainer for one of the on-line dog training programs. I am frequently very surprised when my students come to me for their final stages of the program. Some of the students have dogs who are struggling to be pets. Their dogs don't have even the most basic skills. I am very confused how to help these people get ready to teach when they haven't even learned how to be effective students. I am a really big fan of trainers who have come up through the ranks. There is so much to be learned from walking into a class with an out of control dog and coming out the other side with a great dog/handler relationship. The certification programs have value, but to my mind, they have to be supported by hands-on experience. They should be a compliment to the handler's real-life skills, not a substitute for them.
I have really strong opinions about who should be trainers. If a trainer fails, some owners will use that as a justification to give up on a dog. I have heard so many people say, "I tried everything. I even went to a trainer! He was just a bad dog." The dog ends up being put down or rehomed or hit by a car and the owner feels okay about it because they even tried a "trainer." I want the "trainer" to be really good at their job for the sake of the dog.