Possible Clues:

• Doesn¿t have great expectations to start with ¿ that¿s how Pen saw her brother in the past
• One that's down now, with a high-flying future?
• One billed in the future -- that would be better
• Doesn't have great expectations to start with ¿ that's how Pen saw sibling in the past
• Eventual swan
• Doesn't have great expectations to begin with - that's how the others saw Pen in the past
• Sounds like fowl, mallard, fish and swan maturing over time
• It's not pretty for novice in dodging one of those youngsters with identity crisis planning to swan around later
• One who unexpectedly turns out successful or beautiful
• Cygnet (in the story)