She was a little girl.

In the book Iqad, page 179, it is stated:

"Hussain (PBUH) had a little daughter named Ruqayyah. She was with the prisoners of Damascus, and she cried day and night for her father's separation.

They told her: Your father has gone on a journey. One night, Ruqayyah saw her father in a dream, and when she woke up, she became very impatient and asked for her father.

No matter what the Ahlul Bayt (PBUH) did, she could not calm down. They also started crying because of her crying. They slapped her face and sprinkled dust on her head, and there was a lot of wailing and lamentation.

Yazid said: What happened?

They said: The daughter of Hussain (PBUH) saw her father in a dream and wants him.

Yazid said: Cut off her father's head and place it in front of her, so that she may be pleased.

Then they put the head in a tray, covered her face, and placed it in front of the girl.

She said: O man! I asked for my father, not food.

They said to her: Your father is here.

Ruqayyah pulled aside the cloak, picked up the head and pressed it to her chest, saying:

My dear father! Who dyed you with your blood?

My dear father! Who cut your veins?

Who made me an orphan in my childhood?

My dear father! Who owns women?

Who owns widows and captives?

Who owns foreign women?

My dear father! We have no one after you.

My dear father! I wish I could be your sacrifice.

I wish I had been blind before this.

I wish I had been buried and not seen that your hair was dyed with blood.

So she put her mouth on her father's face and wept until she lost consciousness.

When they shook her, they saw that her soul had left her body.

The women's wailing rose, and sorrow and mourning became new. Every Syrian who heard their voice wept. Men and women wept that day. Then, by the order of Yazid, they bathed him and buried him."

Peace be upon Ruqiyyah