I think that Monica's bouquet/wreath had become several metres long is to imply that Fine did live a fairly long life, while Monica kept working on her wreath, playing in the Gymnasium and waiting for her to come back.
this.
It can't be said that Fine committed suicide since the bouquet was running long.
Although, I only wonder why does Fine looked like a teenager when she came back to the Gymnasium if she did lived a long life.