Thanks for your replies everyone - I found the empty seat came in handy for putting my checklists on
Adam, I got back from my first solo flight at 12:10 so it might not have been me - I was in golf-yankee-tango (C152).
Luckily I didn't get time to feel nervous - it all came as a surprise because I'd actually booked a lesson for my solo next week so I wasn't expecting to do it.