For nearly two years, we thought maybe my daughter was possessed. It felt like every interaction consisted of a sneer and a critical comment. Our family started to wonder if she’d somehow swapped bodies with an angry badger. Then it happened. She started her period. And everything changed again.

Here’s the weird thing. This is one area of parenting that doesn’t get much attention. Many people tiptoe around the subject of “Aunt Flo,” as we used to call menstruation, but I think it’s so important to be open about these issues with our daughters.  I also find that it helps to hear what other people have experienced, particularly other moms.

I now realize that my daughter experienced almost two years of PMS, but it wasn’t until it was over that it occurred to us that her behavior was linked to hormones. Now, when other moms lament that their daughters have become other monster-type people, I tell them about my experience.

Once  your daughter actually starts her period, you will experience the phase of finding what products work for your child. Pads seem like a straight-forward choice, but even then there’s a learning curve. If she starts her period in the summer or if she  does water sports, she will need to use tampons, which she will probably find challenging at first.

Our most traumatic but also hysterical experience in this brave new world was the first day of swim practice when she had to attempt to insert a regular tampon that we had on hand. It didn’t go well. Later, with some pre-planning and the help of an American Girls Body Care book (which includes informative and tasteful pictures) the job was done. We started with the super small size and a plastic applicator, which worked well as a beginning step but had to be replaced often to prevent leaking. My advice? Don’t wait until the last minute: encourage your daughter to try tampons a few times before the day she has to put on a bathing suit.

And then there are the constant mood swings, which to me are more trying than the practical issues. My daughter has probably heard me say, “That’s a reason, not an excuse,” a hundred times. Teaching a tween to deal with her emotional ups and downs can be rough.  I’ve had to explain that it’s normal to feel off or emotional, it’s not okay to lash out at others. Sure. Easier said than done.

One of the most helpful tools we’ve found is a period tracker, which my daughter uses on her smart device. It helps to know ahead of time when mood swings are likely to show up. It also reminds her to stock up on supplies—and reminds me that I may need to buy an extra bottle of wine!