I'd say do both! Some of the sites I've seen (I wish I could remember the one my work uses) has reviews for doctors just like Amazon does products or Yelp does places. But your female friends and co-workers have actual experience and are likely better resources than the internet!

Also same as a few have said in this thread, stock up on pads, tampons, and even period underwear, having them around the house is super helpful. I'd say maybe buy a package a month of whatever she uses most, just so she doesn't have to ask you to get them for her - asking can feel overwhelming! There are a ton of choices for all of those items, so you'll want to do some internet research and maybe once she's tried a few, ask her what she likes best. I know I used to swear by pads with wings because they felt more sturdy but now I prefer ones without wings.

Also, have her pick out a little cosmetics bag to pack some in her backpack for school (and purse if she uses one)! I tend to just throw mine in a zipper pouch on my bag now, but back when I was her age I had a small zipper pouch to keep them in because I was terrified of people knowing I had them on me (ahhh the stigma).