Are you on separate tickets? Checking bags? I don't think I would be super comfortable with a two-hour layover on separate tickets. Jetblue's on-time performance hasn't exactly been ideal. If your flight arrives on time, I don't think you should have many issues, although you might have to wait for your bag. It's about a 15-minute walk altogether from your gate to the Airtrain station. The train itself runs every few minutes during the day, and it'll only take a couple of minutes to get from T5 to T7, but then you'll need to reclear security. Hopefully, that will only be about 10 minutes, but who knows? In all, you're looking at about a 35 minute process from exiting the plane in T5 to making it to your gate at T7, and that's if everything goes right.