Changing/Upgrading my plan

Thanks for your question, Wojceich. In addition to Kglad's suggestion, you might be able to use the steps listed at https://helpx.adobe.com/manage-account/using/change-plan.html to change to full membership. 

The option may not always be available, so if you encounter any problems, or have any questions, then please don't hesitate to reach out to our support team at https://helpx.adobe.com/contact.html?rghtup=autoOpen and follow the suggestions offered by Kglad to allow access to the chat window.

yes, you should be able to do that.  ie, adobe doesn't penalize users for changing plans.

contact adobe support with your student documents handy. there are 3 ways to contact adobe; chat, phone and twitter:

chat:
use a browser that allows popups and cookies
and click here, https://helpx.adobe.com/contact.html?rghtup=autoOpen
in the chat field (lower right), type AGENT
be patient, it can take quite a while to reach a human.

phone:
https://helpx.adobe.com/contact/phone.html

twitter:
tweet @AdobeCare

p.s. if you're contacted by anyone (via email or private message), it's much more likely to be a scammer than an adobe representative. ie, double check for an employee badge if contacted in the forums and look for an adobe.com domain in the email address if you click reply to an email. then check again and be very suspicious. any other method of contacting (or offering to contact you) is almost certainly a scam, https://community.adobe.com/t5/using-the-community-discussions/staying-safe-in-the-adobe-support-community/td-p/12919684/redirect_from_archived_page/true