You were asking how to present your entry.
Check your fair rules ... some fairs are very specific as to how food entries must be plated, wrapped, etc.
And if not ... will be disqualified.
You also asked when to deliver ... gain check with the posted rules.
Each fair is different on that. Plus some fairs will have different rules regarding food entries vs. quilting, etc.
Agree with the others ... it's not time to start experimenting ...
unless you have a lot of willing taste-testers ready, willing and able.
Your family have persuaded you to enter ... the cake, as is ... that they love you for!
Good Luck!