1. The blood part, no. It is different for everybody though, but I haven't experienced major pains yet. You do get headaches though, their painfulness depends on the person. First time periods aren't that painful, but the more you have it the more headaches or pain you get.
2. I use pads, I have never tried tampons so I can't tell if their comfier, but I think pads are best to have because they seem easier to use in my opinion.
3. I'm 11 and I already had it, I don't carry around products because I usually don't go outside (I'm homeschooled) and after you've already had your first one you can pretty much predict when it will come next. If you feel like you might have it soon, I do think it's best to carry them in a backpack or a purse if your out at public places a lot.
I hope this helped! This is my experience with having it so far, so I can't tell if it's the same for you, but I hope some of this helped!