Several here have said that she is probably being marked for having a worldly *boyfriend* as opposed to *friend* such as yourself.
Here's the thing. The JW definition of *boyfriend* includes what anyone else would consider just friendship. For example, if just the 2 of them eat out at a restaurant- that's a *date*. If the two decide to go for a bike ride- it's a date. etc. etc. Simply spending any time alone, even if it is in public is considered *dating*.
The JW view of dating is so narrow that even telephone conversations and emails can and will be considered *dating*. The religion even strongly discourages platonic friendships such as yours. They quote 1 Cor. 15:33 as their reason. As long as your friend is an active member she will be held to these ridiculous standards.