I can't login to the site either
Error! You need to use your e-mail address to login to your Mojang Studios Account.If you haven't done so already, you first need to migrate your Minecraft Account.
then once this appears it says i cannot migrate until 2021
If you still have a legacy Minecraft account (also known as Minecraft Premium) you’ll have to wait until we start the move to Microsoft accounts in early 2021. But no worries — you’ll be able to keep playing Minecraft: Java Edition with your current account until then.
For more information, check out the the Minecraft Java Edition Migration FAQ.