BC/Lab should be perfect for Agility. It will give her an outlet for all that energy, she'll get to jump and jump and jump (and negotiate tables and teeter-totters and A-frames as well), and it will give her something to THINK about.
It made all the difference with my first dog - from a loon she became a pretty solid citizen that I could take anywhere. I was running her in Masters when we retired her from Agility because she was introduced to Retrieving around age 6 or so and preferred chasing nice warm things with feathers. She wound up doing Obedience, RallyO, and K9 Nosework too. Great all round dog, she's just the house queen and general critic now at 13.
Labs definitely need a Job, and that goes double or triple for the BCs. They are obsessive-compulsive workaholics, Labs at least usually have an "off" switch.