My dad's sister filed for him back in 1995, included my brother and I. We both aged out by the time his interview came around in 2009, he migrated in October 2009 and then submitted I130 for us both in 2010. LPR from June 2017. Citizen as of March 2023.
It varies by field office. I'm in Philly, had my interview Nov 22 - asked to go back to my maiden - had my oath today - so 4 months?
Also, they take your green card from you so you'll need to get your passport asap to travel after oath ceremony.