Most law schools begin to announce decisions in February. By the beginning of April, you should know your status at most schools. If you are noticed that a decision has been deferred, you should acknowledge the notification and send any relevant current information, such as an additional letter of recommendation and/or brief account of your present academic work, especially if you are writing a thesis.
Deferring an Acceptance
If you have already applied to law schools, you might be allowed to defer an acceptance for a single year, but such deferments are not automatic, nor can they usually be extended beyond one year; consult individual catalogs for the policy at the law schools in question. If, however, you apply already expecting to defer, you should realize that many schools will not consider your application if you acknowledge that you intend to defer. Given the high costs of applying to law schools, you might consider postponing applying while you gain skills and greater personal direction.
Applying a Second Time
If you apply as a senior and are not accepted, you can always reapply without prejudice. Plan, though, to take at least two years to gain experience and knowledge in a job you enjoy. Develop some skills that will make your next applications significantly different from your earlier ones.