Question more or less medication nativity..?

Okay, so I recently go to my family doctor - due to bleak allergies, and he prescribed me an allergy medication called "Zyrtec".
I go to the local pharmacies and saw that the prices were roughly speaking 3x as much as they are online, so I decided to decree my prescription from a LEGITIMATE ONLINE PHARMACY, AGAIN I DID HAVE A PRESCRIPTION - Upon reading the terms and conditions, it said "full-size signature required", and I thought that meant you have to be 18, seeing as 18 years old is reasonably an adult surrounded by the U.S. ; however, on the UPS website it says an 'adult signature' routine someone 21 years or older.
Now here's my examine:
-The package is surrounded by my name.
- I am 18 years dated.
- I am living on my own.

Will I be able to sign for the transference? Or what do I do? They have already charged my sandbank account for the tablets. Will I be able to sign, or will I own to ask for a refund and a modern prescription since I mailed my weak one in too the pharmacy?Question more or less medication nativity..?
You will be capable of sign they dont ask for id they lately say here you budge and you sign and take it thats it!
if you are living on your own, that also signifies person an adult. lately as 14 year old girls can sign their own consents for have a baby. I would only sign it.