I just got a green card, about cpuiple weeks ago. I'm 20 years old. My mom has been married with her husband for about 6 years now. He is an american citizen. Well after 6 years of their marriage I finally got the green card. Is it time for me to go apply for an american citizenship? Do I have to wait longer?

You must maintain your status as lawful permanent resident for 5 years.
Keep record of your tax return, and avoid having criminal records.