Hey man, let me be brutally honest. I was a model for Diesel for two years. You don't have a model look. You're also too old. I'm 27, I look like I'm 22 and even I'm too old.
Just because you don't have a "model look" doesn't mean you're not good looking to girls. But male models have chiseled faces, strong jaw line, at least 6ft tall and their frames are filled out with muscle.
I'm not trying to be rude or to be an ass. I promise.
Because having an agency and a agent is what gets you jobs, it's kind of like a reassurance that if your good enough to be backed up by an agency then your good enough to work for whoever seeks to hire you.
Think of it in the same way as trying to get a job with references as opposed to trying to get jobs without any.
My father was involved in modding for a while and was offered by several places to be one.