Here is the Ca. Statute:
California Expungement Law
1203.4a. (a) Every defendant convicted of a misdemeanor and not granted probation shall, at any time after the lapse of one year from the date of pronouncement of judgment, if he or she has fully complied with and performed the sentence of the court, is not then serving a sentence for any offense and is not under charge of commission of any crime and has, since the pronouncement of judgment, lived an honest and upright life and has conformed to and obeyed the laws of the land, be permitted by the court to withdraw his or her plea of guilty or nolo contendere and enter a plea of not guilty; or if he or she has been convicted after a plea of not guilty, the court shall set aside the verdict of guilty; and in either case the court shall thereupon dismiss the accusatory pleading against the defendant, who shall thereafter be released from all penalties and disabilities resulting from the offense of which he or she has been convicted, except as provided in Section 12021.1 of this code or Section 13555 of the Vehicle Code. The defendant shall be informed of the provisions of this section, either orally or in writing, at the time he or she is sentenced. The defendant may make an application and change of plea in person or by attorney, or by the probation officer authorized in writing; provided, that in any subsequent prosecution of the defendant for any other offense, the prior conviction may be pleaded and proved and shall have the same effect as if relief had not been granted pursuant to this section.
This subdivision applies to convictions which occurred before as well as those occurring after, the effective date of this section. (b) Subdivision (a) does not apply to any misdemeanor falling within the provisions of subdivision (b) of Section 42001 of the Vehicle Code, or to any infraction. (c) A person who petitions for a dismissal of a charge under this section may be required to reimburse the county and the court for the cost of services rendered at a rate to be determined by the county board of supervisors for the county and by the court for the court, not to exceed sixty dollars ($60), and to reimburse any city for the cost of services rendered at a rate to be determined by the city council not to exceed sixty dollars ($60). Ability to make this reimbursement shall be determined by the court using the standards set forth in paragraph (2) of subdivision (f) of Section 987.8 and shall not be a prerequisite to a person's eligibility under this section. The court may order reimbursement in any case in which the petitioner appears to have the ability to pay, without undue hardship, all or any portion of the cost for services established pursuant to this subdivision. (d) Any determination of amount made by a court under this section shall be valid only if either (1) made under procedures adopted by the Judicial Council or (2) approved by the Judicial Council.
1203.45. (a) In any case in which a person was under the age of 18 years at the time of commission of a misdemeanor and is eligible for, or has previously received, the relief provided by Section 1203.4 or 1203.4a, that person, in a proceeding under Section 1203.4 or 1203.4a, or a separate proceeding, may petition the court for an order sealing the record of conviction and other official records in the case, including records of arrests resulting in the criminal proceeding and records relating to other offenses charged in the accusatory pleading, whether defendant was acquitted or charges were dismissed. If the court finds that the person was under the age of 18 at the time of the commission of the misdemeanor, and is eligible for relief under Section 1203.4 or 1203.4a or has previously received that relief, it may issue its order granting the relief prayed for.
Thereafter the conviction, arrest, or other proceeding shall be deemed not to have occurred, and the petitioner may answer accordingly any question relating to their occurrence. (b) This section applies to convictions which occurred before, as well as those which occur after, the effective date of this section.
(c) This section shall not apply to offenses for which registration is required under Section 290, to violations of Division 10 (commencing with Section 11000) of the Health and Safety Code, or to misdemeanor violations of the Vehicle Code relating to operation of a vehicle or of any local ordinance relating to operation, standing, stopping, or parking of a motor vehicle. (d) This section does not apply to a person convicted of more than one offense, whether the second or additional convictions occurred in the same action in which the conviction as to which relief is sought occurred or in another action, except in the following cases:
(1) One of the offenses includes the other or others. (2) The other conviction or convictions were for the following: (A) Misdemeanor violations of Chapters 1 (commencing with Section 21000) to 9 (commencing with Section 22500), inclusive, Chapter 12 (commencing with Section 23100), or Chapter 13 (commencing with Section 23250) of Division 11 of the Vehicle Code, other than Section 23103, 23104, 23152, 23153, or 23220. (B) Violation of any local ordinance relating to the operation, stopping, standing, or parking of a motor vehicle. (3) The other conviction or convictions consisted of any combination of paragraphs (1) and (2). (e) This section shall apply in any case in which a person was under the age of 21 at the time of the commission of an offense as to which this section is made applicable if that offense was committed prior to March 7, 1973. (f) In any action or proceeding based upon defamation, a court, upon a showing of good cause, may order any records sealed under this section to be opened and admitted into evidence. The records shall be confidential and shall be available for inspection only by the court, jury, parties, counsel for the parties, and any other person who is authorized by the court to inspect them. Upon the judgment in the action or proceeding becoming final, the court shall order the records sealed. (g) A person who petitions for an order sealing a record under this section may be required to reimburse the county for the actual cost of services rendered, whether or not the petition is granted and the records are sealed or expunged, at a rate to be determined by the county board of supervisors not to exceed one hundred twenty dollars ($120), and to reimburse any city for the actual cost of services rendered, whether or not the petition is granted and the records are sealed or expunged, at a rate to be determined by the city council not to exceed one hundred twenty dollars ($120). Ability to make this reimbursement shall be determined by the court using the standards set forth in paragraph (2) of subdivision (g) of Section 987.8 and shall not be a prerequisite to a person's eligibility under this section. The court may order reimbursement in any case in which the petitioner appears to have the ability to pay, without undue hardship, all or any portion of the cost for services established pursuant to this subdivision.
You can see an attorney about filing a petition for expungement. If your record is expunged, the event will be as if it never happened; you're rights will be reinstated in every aspect - you can buy a firearm, vote, etc.