If your folks are cool with it get them as a guarantor, meaning one of ur folks names are on the loan as well as yourself, but deposits coming out of your account. When I was 18 last year I got 15k out with zero credit history and in 1 month of having a full time job. Gives the bank some piece of mind if u cant make payments they'll hassle ur folks.
Not sure why the banks didn't recommend that option to you..