Many first-time offenders make critical mistakes, like pleading guilty under the assumption they will get leniency. Retaining a defense lawyer is highly advised, as any criminal record has the potential to create problems for you. Defense lawyers know how to interact with the prosecution and court to reach an agreement on a plea deal.
Depending on your situation, your best option may be going to trial. The justice system is confusing and your case may be lost based on any procedural snag. Consequences that can follow you through your career are worth the investment of a criminal defense attorney.