I wouldn't worry too much. Take it as one of the joys of being young. They obviously get lots of newbie travellers who don't know the right queues etc.
I was travelling with an infant from FRA to LCY in business (points), and when I boarded the FA said "sit down and I'll get you the infant lap belt", so I sat in my seat (2A), and she shortly came to me and asked me where I was sitting. She was a bit stunned when I said I was sitting in my allocated seat. They obviously don't get too many infants in business on that sector.