Take her to Ulta and Sephora and have her try some. They've always got samples - usually the more expensive brands but she can get an idea of what colors she likes and then get the cheaper ones. You can also take her to the makeup counters at Macys/Nordstroms/etc. I've found the makeup ladies are usually pretty good with color choices.
You might also think about a subscription box like Birchbox or Ipsy. My DD LOVES them.
Recently, I took my teenaged DD for a makeup lesson with Marti at Tica Beauty
https://www.ticabeauty.com/ in Falls Church It was $75 for the lesson and she did a fabulous job. She explained to my DD why she did what she did, talked to her about brushes, tools (and never to share with her friends) and talked about everything from what to avoid to eyebrow shaping. There was no pressure to buy her products but we did get some really good products. the look was nicely natural and I really appreciated my DD hearing from someone other than her mother what DD should avoid.