Hi @beatriznogueira, welcome to the Spotify Community!
Try to log out/ log in and see if your Premium activates. If a log out/ log in doesn’t work check your inbox. Did you get a confirmation email after upgrading?
If you have your subscription confirmation and it’s still not appearing you may have created a second account and upgrade that one on accident. Please follow this guide in our FAQ to find out if you have a second account.
Let us know if you have any questions. Thanks!