how to get student discount apple music on existing account

Hello cauams,

Thank you for reaching out to Apple Support Communities.

These steps can help you get an Apple Music student subscription:

"How to get a student subscription to Apple Music

1. Open the Apple Music app or iTunes. 
2. Go to Listen Now or For You.
3. Tap or click the trial offer (one trial per person or family).
4. Choose Student, then tap or click Verify Eligibility.
5. You'll be taken to the UNiDAYS website where you'll need to follow the onscreen prompts to verify your enrollment. After UNiDAYS verifies that you're a student, you'll be redirected back to the Apple Music app or iTunes.
6. Sign in with the Apple ID and password that you use to make purchases. If you don’t have an Apple ID, choose Create New Apple ID, then follow the steps. If you're not sure if you have an Apple ID, we can help you find out.
7. Confirm your billing information and add a valid payment method.
8. Tap or click Join."

Additional details can be found here: Get an Apple Music student subscription

If the issue persists, please reach out to Apple directly.

You can do so by going to Get Support

Cheers!