I'm seriously considering taking the PBW course. But I have a couple questions.
1) How old should you be? I'm 17 and I'm wondering if taking the course would be a good idea.
2) System requirements and internet speed? What should I have?
I've registered for my PWB session. Though the best thing would be to inquire with the OffSec team. I suspect your age might be an issue. Students have to virtually sign a legal agreement. Which could be problematic while you're still considered a minor. I'd suggest asking on the IRC channel: #offsec on irc.freenode.net
Any system that runs BT/Linux good enough for you. There is a BT VM image that's optimized for the course. As for connection speed. The official requirement is: "high speed ADSL or cable connection (512/256 minimum)" . As well as what's on the site: basic Linux skills, though good knowledge with Linux and Windows helps. Also solid understanding of networking & TCP/IP is key. Knowledge of bash scripting and language (python, perl) helps but not a must. You can typically learn enough during the course.
Just my two cents