naming help

need your opinions:) apparently I have settled on a name and didn't even realize it. Just started referring to her that way:)

BUT I can't figure out how I should spell it. I am looking for Eye-lee as the sound.

Eiley

Ailey

Isley

Iley

OR Should i go with Isla (eye-luh) which is a fairly popular name in scotland, and call her eye-lee as a nick name and then she has a choice for a more "big girl" name when she gets older?

I have worries with how names will grow with them:) with Piper I got on FB and MS and asked everyone over the age of 25 I could find how they liked their name as a kid, and how they like it now

HELP!!! :)