When my mom had me they thought I was a month early, but I was born with long finger nails and eyelashes. My mom had a completely normal period when she was pregnant with me. I was conceived a month before they thought.
I'm have to agree with My Peanuts' mom - My son was born right where they said, but he had fingernails and toenails so long they curled over his fingers and toes, full eyelashes and sideburns. Poor baby needed a haircut right away. After he was born the doctor said he was 9.5-10 month baby.

I'd definitelty suggest a test. Would put your mind at ease - either way. Here's hoping that it comes out however you would like it to be.