If they want to it's available to them. I recommend anyone willing to learn first-aid and advanced first-aid to do so. I wouldn't make it a requirement though. Especially at that young of an age. I think that's a bad idea to be honest.
I was in 7th grade or so when I learned. It was part of a Red Cross babysitting course I took. I see no issue with the age or even earlier learning it. I actually think everyone should know CPR and should take refresher courses every couple years, so it becomes second nature. I wouldn't force it on anyone, though think it should be strongly encouraged. It's hard to understand just how valuable it is until you need it, and by then, it's too late if you don't.
Benedict Arnold 