Unfazed beats expert
Being calm matters more than being an expert. A steady "okay, what do you need?" beats a nervous silence every time.
Buy the pads. Restock the bathroom. Put a hot water bottle on the sofa. These small acts tell her this isn't something to hide.
Learn the three basics
1. Cycles vary. Somewhere between 21 and 45 days apart is normal for teens; bleeding for up to 7 days is normal.
2. Some pain is normal, but pain that stops normal life is not — that's a GP conversation.
3. Mood shifts in the week before a period are a real, hormonal thing. Not "drama".
If you're a foster or kinship carer
You may not know her history or when she started. Ask her, gently and privately: "Do you have what you need for your period? Is there anything I can pick up?" No follow-up questions unless she offers them.
Keep supplies visible and freely accessible — a basket on the bathroom shelf, not tucked away.
When to bring in another adult
If she'd rather talk to a woman about something specific, offer it as an option, don't take it as a rejection. A trusted aunt, older cousin, school nurse, or GP works. Your job is to make sure she has someone — it doesn't always have to be you.