That definitely helps. It means she came from a hatchery, not from someone's backyard flock. So she's not a completely random mix. Instead, she is either a pure breed, or else a mix that was bred for a specific purpose (like Sapphire Splash or Leghorn-based Easter Eggers).
The color and body shape could also go with an Andalusian. They are "supposed" to be blue, but in practice they come in black, blue, and splash (because that's what happens when you breed two blue chickens.)
But I would expect a much larger comb on an Andalusian or a Leghorn of this age.
It seems likely, but I can't be entirely sure.
It definitely does not sound like a typical single comb. Single combs are the ones that look like you could comb your hair with them: a single row of points standing up.
Sapphire Splash should have a single comb, right?
I agree that a single comb will not prove anything, but a not-single comb will rule out Sapphire Splash and leave Easter Egger as the only likely option.