This is easily in my top 5 favorite comic stories of all time. I highly recommend it. Even if you dislike X-23 for whatever crazy reason, this is a great story and worth a read.
I'd also recommend the continuation of it, Target X. It's not as good but it still has a lot of that heart that Innocence Lost has. Also it introduces Kimura, who is a character designed to stop X-23. She is a great villain.
It's these two books that made X-23 one of my favorites.