How long after the Bella and James incident is the prom. Bella mentions she thinks Jacob has grown since she last saw him, has some time past?
In "Twilight" by Stephenie Meyer, she is not always very specific about the month and time of when things are taking place, but you can deduce approximately when the time period is. For example, Bella begins attending the school in Forks when students are obviously in full swing and have been attending school for some time.They even mention having been waiting for her arrival. When Bella has her scary encounter with James, she has some very bad injuries which puts her in the hospital, and since prom is usually in May or June, you can assume that it has been about a month or two.
If I had to put my finger on it happens about a couple of weeks to a month after the incident. I say this because when the incident happen it was really hot when Bella went to save her mom which could indicate that summer was really around the corner or already or only a couple of days away. And of course most proms take place in May so being that she still has the cast on it could have happened a couple of weeks to a month ago.