Only a juvenile record can be sealed. I assume you are an adult. Therefore your only option is to seek an expungement.
You can read Penal Code sections 1203.4 and 1203.4a. One deals with cases in which you are placed on probation and the other when no probation is granted. If you are on probation you must wait until you are off to get the case expunged. Without probation you must wait one year. Therefore, it sounds like it is too early to apply either way. But even if you did it would not "seal" the conviction. It just results in a dismissal of the case. A background check will still show the arrest and the dismissal.
I have to agree with my colleague.
"Sealing" of one's record is afforded only for juveniles or minors. The only remedy you may have is to attempt to expunge the matters. Expungements are available on misdemeanor cases asking the court to withdraw your guilty plea and in its place enter a not guilty plea, then dismiss the matter.
The first thing you should do is go to the courthouse in which you were convicted and request from the Clerk's office a copy of your minute order for each case. If you have the case numbers, that will help the clerk. If you do not have the case numbers, the clerk will likely ask for your name and date of birth and do a search. The information on the minute orders will be necessary should you attempt an expungement yourself or you decide to hire counsel to assist you with the process.
I would suggest contacting a reasonable attorney to assist you with the expungement process. Not that you could not do it yourself, but having the assistance of an attorney will make the process that much easier for you.