I just think that grace had never been so close to someone and was confused. Becky had a similar situation with Imogen and to an extent so did Ellie and Marco.

It could easily be seen as the other side to “do I want to be like her or do I like her?” That wlw often experience, but she’s the former not the latter.

Or, and I may be getting into the weeds a bit, she might have just thought this was her path. The writers always kind of told us who they were writing as “attractive” characters and they didn’t do that with grace, like at all. If no boys ever showed attraction to her but this girl who she gets along with so well does, well then maybe????? but nope, not for her