I recently attended another client's naturalization interview. English is not her first language. Although she was nervous, she did great and is now a United States Citizen!
I cannot stress too much how important it is to study the questions that you could be asked in the interview. Practice with your family members. Practice with friends. Practice with co-workers. It is important that you can answer the questions correctly, and not be confused by the accent of the person interviewing you.
As soon as you make up your mind to apply for naturalization, you should start studying the questions and practice writing your responses in English.
Remember - the interview starts as soon as the Immigration employee greets you. You should smile and be able to have an informal conversation with the Immigration employee.
Making the decision to become a United States Citizen is important. A United States Citizen enjoys many more rights and privileges than a Lawful Permanent Resident. If you are able to apply for naturalization, I strongly recommend that you do so. Another reason you should consider naturalizing now is that it may be more difficult to naturalize in the future.
There are plenty of resources available, including sample interviews on YouTube. Information for those considering naturalization can be found at this USCIS link: https://www.uscis.gov/citizenship/learners .