I was on the old"Premium" plan structure and was allowed "Unlimited" forms.

Premium Accounts are based now on Bronze plan subscription which limits your forms to 25.
You have 29 forms as seen below.

Your forms are grandfathered. If you archive or delete your forms in order to open available space, you can create new forms. You will only have a problem when you need to create a new form.

Or, if you upgrade your account to SILVER, you will be able to create forms up to 100.
I hope it helps.