The police may have given you a form that describes your rights. By signing that form, you may have admitted that you read, understand, and waived your Miranda rights. In addition, the police only need to read you your Miranda rights if they intend to interrogate you. If they don't interrogate you, there is no need to read you your rights and anything you say may be deemed a voluntary statement.
Even if you make incriminating statements during questioning before being read your Miranda rights, the suppression of those statements might not lead to the dismissal of your case. The police may have evidence they obtained from other sources that may be sufficient to prove your guilt.