This is not the biggest headache in the world. Talk to your PO TODAY and ask what you can do to make this right. They will have a solution. There is a class available every day in metro Denver that will most likely meet your needs.
It is not a matter of extending the deferred judgment. You can solve this problem. Stop putting things off!!
In no way am I offering you legal advice, and in no way has my comment created an attorney-client relationship. You are not to rely upon my note above in any way, but insted need to sit down with counsel and share all relevant facts before receiving fully-informed legal advice. If you want to be completely sure of your rights, you must sit down with an experienced criminal defense attorney to be fully aware of your rights.
Technically a deferred sentence can only be extended for 90 day for the payment of fines only. However, the court can set out a review date for the revocation of your deferred sentence to allow you more time to complete your requirements. If you show up to court with an appointment for the theft class already made, then you'll be just fine.
Talk with your PO about giving you extra time to complete the theft class. The probation department has 30 days passed the tie of your deferred judgment due date to file a motion to revoke your deferred judgment.
The information provided in this answer does not create an attorney-client relationship and is not considered to be legal advice. Mr. Leroi answers questions on Avvo because he strongly believes in public service from his years as a judge, magistrate, and prosecutor. If you need to ask any follow up questions because my answer did not fully address your question, feel free to call Chris or post an additional question. Thank you.