The first time I used a tampon it was because I was 12 and I really wanted to go swimming. Maybe try it with her, not sure how a pad would work...it definitely would be hard to hide too.
Your daughter can go swimming, the bleeding tends to stop when we get in swimming pools.
I have many friends who go swimming with their periods just wearing a pad. I personally always use a tampon if i want to go swimming with my period, I have friends who have told me that even though they swim in their pads that the water tends to prevent them from sticking to their bathing suit bottoms.