PLEASE Explain the Difference Between BIRKIN and KELLY ???

Queen Victoria 2,
As others have noted, this is not a silly question at all - they both have the same "chassis" and the differences are very subtle, unless you are really studying this thing.
Here's my take on the differences:
1. The kelly bag has a detachable shoulder strap; the birkin bag does not. The birkin bag has two top handles and the kelly bag has only one. The top flap of the kelly bag is one continuous piece from the back of the bag. The top flap of the birkin bag is sewn into the back side of the bag in an top arc.
2. While they both come in various sizes, eg, extra small, small, medium, large and extra large, the smaller kelly bag are shoulder bags and the larger kelly bags are essentially briefcases. The larger birkin bags are essentially tote bags, whereas the smaller ones are essentially lunch boxes. Oops, I meant, handbags.

3. Ok, now here are the REALLY IMPORTANT differences:

a. A kelly bag costs a heartstopping amount. A birkin bag costs more than a heartstopping amount.

b. Kelly bags are hard to come by. Birkin bags are extraordinarlly hard to come by.

That having been said, the Chicago store is terrific, and the staff is great. I wouldnt be surprised if you returned with a kelly bag or birkin bag! Have a great time in the Windy City.