American citizenship is the most secure form of immigration status, it cannot be revoked except in very specific fraud circumstances, and it permanently eliminates the risk of deportation. If you qualify, it's a step worth taking.
Main Requirements
To apply for naturalization you need: be a permanent resident (green card holder) for 5 years (or 3 years if married to a US citizen), be at least 18 years old, have resided continuously in the US for that period, have been physically present for at least 30 months of the 5 years, be a "person of good moral character," and pass the civics and English test.
The Naturalization Test
The test includes two parts: English (reading, writing, and speaking) and civics (100 questions about US history and government, of which the officer asks up to 10 and you must correctly answer at least 6). If you are 65 or older and have been a permanent resident for 20+ years, you may take the civics exam in your native language and only study 20 special questions.
When Criminal Records May Complicate the Application
If you have arrests or criminal convictions in your history, consult with an attorney before applying. Some convictions can affect the "good moral character" requirement or even make the applicant deportable if USCIS reopens their immigration case. An attorney can review your history and evaluate whether the citizenship application is safe for you.