Tween period kit

My daughter is 11.5 and I'm starting to think about her getting her first period soon. I've had a hysterectomy so it's been a while since my last period. Any advice on what to include for a period kit for her backpack? Should I put in extra underwear or leggings too?

What's your favourite period underwear, how many do you need or what do you use for products?

Any advice on this topic will be great!!