From Newfoundland: My mother’s mother died so my grandfather married a new women and that new women Is my girlfriend’s grandmother’s sister… so do that mean me and my girlfriend are related?
The simple answer is “no”. You are not biologically related and an intimate relationship with her would not be incestuous. If you are interested in each other and the real question is whether it is okay for you to date, I think it’s fine.
Depending on how your family defines family membership, the two of you may be considered as part of the same extended family. But that is a different matter. Families often embrace people who are not biologically related.
I wish you well.