My education about my period started and ended with a pad being thrown at me on the day it started.

No tampons were allowed. (Yes, I think this was a bit harsh)

Those 'U' brand ones are really slim and small...maybe give them a go?

Re Hymen - I have NO idea when mine broke as I didn't feel it, but was also very sporty and a dancer. Pretty sure it was already gone when I lost my virginity becuase there was no pain or blood involved.

At 11/12 I was terrified of using a tampon - but this was probably a result of poor education, as I said. I reckon give them to her....if she doesn't like them, she won't use them!