First egg from my new batch of pullets--who laid it?

This spring I got 10 pullets from the store, one was almost a month older.
That one that's a month older is my spangled OEGB Jace.
On April 30th, I got 5 black sexlinks and 4 EE's. I got my first obvious pullet egg just now. It's the size to either be a bantam or a large egg, so I'm a little confused. I have 2 full sized banties and I compared their egg to this and it was the same size, with this one being a little skinnier.
So, who do you think laid this? Probably not my EEs, but was it Jace or the sexlinks?

This was taken next to a regular size egg for comparison.

I can provide more details or pictures of the hens that might have laid them if needed.