When I was in my late teens, I aspired to be a professional photographer. While I did intern and fall under the wing of some "average" folk in terms of mentoring, I always looked past them, to the ones who did the very best work and had the greatest success.
In other words, even though I respected and acknowledged those who were climbing the ladder, I aspired to the highest levels of talent and success in photography and kept that in my sights as the primary goal. I also did not listen to people who now post things like they would rather be a plumber than a photographer or even my dad grinding away at dentures in his home dental tech lab saying "Why are you wasting money on camera crap when you could be saving up for a car? Every boy and his dog wants to be a photographer".
I have spent the last 23 years of my 45 year old life as a full time professional photographer, in regard to the majority of those who earn a full time living at anything in photography, I am considered fairly successful in terms of what I get paid and what I get paid to shoot and that has mostly been the case in the past 10 years. I am now in transition to doing nothing but wet print based fine art work for the rest of my career, a lot of it landscapes. I succeeded in the first 23 years because I listened to *my* inner voice, I made my sacrifices and I emerged from my nightmares to live my dreams...
If you want to be a successful at anything, you have to know deeply where your strengths and talents lie, you have to be honest with your self about your abilities and build off of those strengths and talents and ultimately, you have to focus on those who are making it happen, not those who are not.
People who succeed don't just believe they could, they know they will....and they are.