Because she is older and has more experience and strength
Grendel's mother is more powerful than Grendel and is driven by revenge, making her a more formidable opponent. She is also more cunning and strategic in her attacks, which makes the fight more challenging. Additionally, her underwater lair gives her a tactical advantage over Beowulf.
While Grendel's mother is hard for Beowulf to defeat, he IS able to use a sword, where as he has to battle Grendel bare handed.
Under water, where Grendel's mother lived.
Beowulf and Grendel's mother fought in her underwater lair at the bottom of a dark, eerie mere (a kind of lake). The battle took place in the depths of the water, adding to the suspense and danger of the encounter.
While Grendel's mother is hard for Beowulf to defeat, he IS able to use a sword, where as he has to battle Grendel bare handed.
In the epic poem "Beowulf," the narrator refers to Grendel's mother simply as "Grendel's mother." She is not given a personal name in the story.
Beowulf fights Grendel's mother, and kills her. He kills her with a sword that was made by giants, and he splits her into two.
Beowulf followed Grendel's mother's tracks to her underwater lair after she attacked Heorot. He dove into the lake and ultimately battled and killed her with the help of a magical sword he found in her lair.
Grendel's mother's behavior is driven by a desire for revenge and protection of her offspring, rather than simply being wicked or unreasonable like Grendel. While she is a formidable opponent, her actions are more motivated by a sense of duty and loyalty rather than pure malice.
After Grendel's mother attacks Herot and kills one of the warriors, she takes Grendel's arm as revenge for his death.
In most versions of Beowulf, she has no name that is given; she is just called "Grendel's Mother".Some variations give her the name "Enchidna"
Fighting Grendel, Grendels mother and the dragon once he returns home to Geatland and is crowned king.
Grendels arm If its after the fight with Grendel's Mother then he took Grendel's head, the sword-hilt of the sword he used to slay Grendel's mother and cut off Grendel's head, and of course Hrunting the sword he originally brought to slay Grendel's Mother which was ineffective against her tough hide.