Hey there kendrazuercher,
Thanks for reaching out to the Apple Support Communities.
While there doesn't appear to be a limit to the number of photos, have you ensured that you added your daughter to the People album as shown in this link here: Use the People album in Photos on your iPhone, iPad, or iPod touch - Apple Support
Add someone to the People album
1. Open a photo of the person that you want to add.
2. Tap the Info button
, then tap the face of the person with a question mark.
3. Tap Tag With Name and type the person's name or tap the name if it shows up.
4. Tap Next, then tap Done.
Put a name to a face
Photos suggests names from your Contacts, but you can manually add a name to someone that's already in your People album: Here's how:
1. Open the People album, then tap the thumbnail of the person that you want to name.
2. Tap Add Name at the top of the screen.
3. Type the person's name or select their name if it shows up.
4. Tap Next, then tap Done.
If so, then the next best option would be to reach out to Apple Support directly for additional help at this link here: Get Support - Apple
Best regards.