LOL. Ask a question without providing relevant information, get an answer without relevant information.As soon as you are eligible.
I have my GC - when is the earliest I can apply for Citizenship?
It depends..if you're married to a US citizen, then up to 90 days before your 3rd year wedding anniversary under LPR status.
If you're applying regular route, then up to 90 days before your 5th year LPR anniversary.
Both options require to meet continuous residency and physical presence requirements.
Start by reading the guide to see what is required to apply.
www.uscis.gov/files/article/M-476.pdf