Can I still apply for citizenship if I have a shoplifting charge four years ago?

If the charge was dismissed you probably should not have any concerns, but if you were found guilty, then it might lead to the conclusion that you are not a person of good moral character. An applicant for US citizenship must show amongst other things that they possess good moral character. And even then, the required period within which an applicant must show good moral character is the last 5 years immediately before the filing of the application. If you were indeed convicted of this shop lifting charge, then I will suggest that you wait for one more year before filing your N-400 application.

Yes, but I suggest that you wait until the shoplifting conviction is at least 5 years old.

It depends on what charges you were convicted of and the sentence imposed by the court. But at a minimum, you should wait at least 5 years from the date of the conviction, when you were released from custody, or when you completed your probation, whichever is later, before you file your N-400 application.