Applying for GC for parents after gettign citizenship

Can someone tell me how long it takes for parents to get GC after I get my citizenship? Is it very long as 10-12 years? I heard that parents of a citizen fall under the unlimited category and hence can be immediately eligible for Adjustment of Status or Consular Processing?

Thanks

Parents of US citizens (as long as the US citizen is at least 21 years old) in fact are classified as immediate relatives, and there is no quota for immediate relatives.
The processing time should be less than 1 year for CP. For AOS, the I-485 processing time at the local offices is currently around 1 year as well (check the times on a number of websites.)