dianeolsen wrote:…How to add a new person? I have so many photos of her and named an album for her.
Do images of your daughter have a little circle at the bottom with her face?

If there's a face with a question mark, like the one of my wife's aunt above, then you can click on the circle and supply a name. If there's no little circle with her face, then Photos hasn't seen what it recognizes as a face-- and, I'm sorry, but there's nothing you can do about it.
Many of us put names into the Info Caption filed to help in searches. You've put her in her own album, which we also do. Frankly, I use the People album not as the end result, but rather as a help to add keywords and captions, which are more useful. For instance, those actually become part of the metadata for a picture that will export with the photo, while Face IDs do not.