Welcome to Knitting Help!
You can deal with the remainig 15sts in the easiest way possible, just ignore them for the moment. Eventually the instructions will tell you what to do with those sts. Maybe you'll do a final row across all sts or you may have some rows that gradually incorporate those sts. Read a bit further in the pattern and you'll see that those sts are brought into the shawl.
And don't worry, plenty of weather ahead for you to wear the wrap.