I used pads for the first month, hated them, came home form school after whinging to mum about how revolting pads were and found a packet of carefree tampons on my bed! lol

Never looked back.
Only time I used pads was overnight or when I m/c...

Personally, not sure I understand the issue with her inserting tampons? As Jen said, her hymen may not be intact now, and using tampons doesn't make you any more 'impure' than not using them...
WRT to risk, it will leak before she is at risk, one leakage and I promise she won't forget again in a hurry

Make sure you sit down with her and go through the info in the pack, also probably a good idea to teach her how to retrieve it if she loses the string, the health risks etc and how to maintain cleanliness before and after inserting them.
Now is probably an excellent time for her to sit down with a mirror and have a look at herself, see where everything is and use it to practice inserting them. Gotta know the mechanics so she knows when they are in properly etc.

Start with the smallest size for her flow and I am sure she will be fine.