New Student Discount

You don't.  The intro rate is for new members only for the first 12 months.  After that you pay $29.95/month student rate until you cancel or graduate, whichever comes first.  Thereafter, you pay the regular rates.

As far as I know, a NEW STUDENT discount is not available to someone who already has a subscription

But... ask Adobe

This space is provided by Adobe, but it is not Adobe support
Sorry, nobody here can help with an account or payment problem
This is a public forum, you need the link to Adobe support, not other users
Be sure to remain signed in with your Adobe ID before accessing the link
Do be aware that Adobe's staffing is impacted by the virus, so wait times are long
-make sure that your browser does NOT block ads, scripts, or pop-ups
-you must also allow 'cookies' in your web browser for the link to work
This link will go directly to the chat option
Type "Agent" in the chat box to bypass the chatbot and be connected to a person
-Meaning type in the word Agent without the quote " " marks
https://helpx.adobe.com/contact.html?rghtup=autoOpen
- or https://helpx.adobe.com/contact/phone.html
.
Adobe does NOT do support by email, so beware of answering anyone who sends you a private message
-click for more information about scammers https://tinyurl.com/10791730