12-12-2013 03:19 PM - edited 12-12-2013 03:20 PM
Visit BlackBerry World from your phone and search for BBM. When the app opens, look down near the bottom to see what version it is. I believe BBM 8 is available for your phone but doing a search in BlackBerry World will confirm that. If the version shown is lower than BBM 8, then it's not available for your phone. Only apps that are compatible with your phone will be displayed when you do a search from your phone.
P.S. Typing www.blackberry.com/bbm in your phone's browser will take you right to the download page in BlackBerry World.