In law, being innocent is determined by applying the law to the facts. The facts are determined at trial. If you believe that you are innocent, you should consult with a criminal defence lawyer about what facts may be proven at trial and whether the law is on your side.
Just because you believe you are innocent does not mean that you will be found not guilty at trial. We recommend that you hire a lawyer to make sure that your trial goes to plan and you are found not guilty of any criminal wrongdoing.
The length of time it takes for a trial to take place after you are charged is highly dependent on a number of factors, such as how complicated your trial is, how serious the charges are, how many witness have to testify, and so forth. Typically, trials do not occur until more than a year after the charges are laid.