How about becoming something that will actually pay the bills and then pursuing one of your dreams in your spare time? Do you know the odds of you actually making it big enough to pay the bills? They're pretty discouraging, no matter how good you think you are.
well really, it depends, how much experience do you have with martial arts? you see, being a "good fighter" is a relative term, a black belt would generally be considered a "good fighter" but i can crush most black belts in 2 minutes or less, so unless you are incredibly confident, and have the experience to match yourself up against newer and stronger opponents, then i wouldnt reccomend UFC for you, however, you can put fighting skill (even if it isnt that much skill) into practical application within football, such as targeting a certain place to make a tackle more effective, or blocking people from tackling you.
Whatever your best at then go for that shot of achieving it.... which in my opinion UFC is better than football cause I can't get myself into watching football so I would rather watch a good fight instead LOL :)