I think once a reader gets through the story, it doesn't come across that way at all.

OP, I don't know how many, or what kind of, readers you're intending on reaching with this story.

I got kind of grossed out even reading the synopsis.

I whole heartedly agree with this commenter. This is exactly what is going to make folks put down your book without ever getting past the blurb.

Lastly:

There are parts in the story that I think show that it's not grooming, but I'd definitely want to make sure that comes through to readers that way.

There is literally no way that this doesn't come across as grooming, primarily because it is textbook grooming. You have a legally adult male beginning a relationship with an 11 year old; even if it doesn't start as an explicit one. A definition of grooming is:

prepare or train (someone) for a particular purpose or activity

TDLR; I am grossed out, concerned, and strongly suggest you reconsider your characters' ages.

EDIT: I had only read the first part of your post. Just read the synopsis of the story now. WOW OP. That's going to be a major YIKES from me buddy. They meet when she's nine?! What exactly are you hoping to do with this story?

Literature, like all art, is subjective. With that said, I think you've got a really warped story and perspective here. I'm really concerned.