Usually, you must complete the school requirement (it's mandatory for a DUI). If you don't, the DMV may suspend, revoke, or refuse to renew your license. It doesn't matter how much time has passed.You should call the DMV and see if they will still require you to attend school. Sometimes they review decisions on a case-by-case basis, and if you have had a clean record since 1990 they may clear your record without you having to attend school.