At her age the most important thing is the routine. Kaeso range though is amazing for reducing dryness. My clients love it. It's an affordable range but is very good. If she's reacting sometimes, she might have sensitive skin but so many people think they have it when they don't so I would get her a facial before buying anything if you dont do them yourself. A 'my first facial' type thing or a prescriptive one would be even better.
But getting her into the cleanse, tone, moisturise routine is the most important part and if you aren't sure, something professional is better than high street. Wish someone had stopped me buying cheap stuff when I was young.
Hope this helps!