I'm a subcontractor who did a private project and I Haven't received my last payment, change order payment and Retainage payment. The sum is around $40K.
Yes. You must record your lien within 30 days of recordation of a Notice of Completion, or within 90 days of completion if no Notice of Completion was recorded. When I say "completion" I mean the entire work of improvement, not just your scope of work. If you need help, let me know. Good luck.
It certainly sounds like you can - and should - file a mechanic's lien as soon as possible. Without knowing additional details, like the state the work was performed in and when your last day of work was, it is hard to be able to ascertain whether you are still inside your timeframe, however, for a mechanic's lien. An experienced construction lawyer in your jurisdiction can help you figure out your next bext steps.