I’m sorry to be a nay-sayer, but since it sounds like you’re not set on the name yet and still asking for opinions, just wanted to weigh in and say that maybe you might want to consider some other first name options.
Of course, if you love [name]Gillian[/name] you should go for it. But there’s just something about it that feels rather abrasive somehow. I think the name itself is just not sure what it wants to be - it’s got this soft G upfront, which starts it off with an old world kind of feel (like [name]Georgia[/name] or [name]Gemma[/name]), but then the first sound you hear is [name]Jill[/name], which feels more modern and to the point, and then you flow into the jilly sound, which kind of sounds like jelly and all of a sudden the name is girl and frilly, almost sappy, and then it ends with an n, as if it’s trying to be serious again. On the other hand, you may like its ‘eclectic’ feel and the fact that it doesn’t fit in any one box or style. To me, it just sounds off beat.