Because he had nine hundred chariots fitted with iron and had cruelly oppressed the Israelites for twenty years, they cried to the Lord for help.
Judges 4: 3 NIV

So Deborah went with Barak to Kedesh. 10 There Barak summoned Zebulun and Naphtali, and ten thousand men went up under his command. Deborah also went up with him.
Judges 4: 9b - 10 NIV
In the meantime Heber the Kenite had set up his tent close to Kedesh near the oak tree at Zaanannim. He had moved away from the other Kenites, the descendants of Hobab, the brother-in-law of Moses.
Judges 4: 11 GNT

Who's that coming up the road... Omgosh! It's him, it's Sisera! Now what do I do?
18 Jael saw him coming, so she went out to meet him and said, “Sir, come into my tent. Come in. Don’t be afraid.” So Sisera went into Jael’s tent, and she covered him with a blanket.
19 But first, Sisera asked Jael for a drink of water. Jael had some milk in a bottle made from animal skin. So she gave him a drink of the milk and then covered him up.
20 Then Sisera said to Jael, “Go stand at the entrance to the tent. If anyone comes by and asks you, ‘Is anyone in there?’ say, ‘No.’”
21 But Jael found a tent peg and a hammer. She quietly went to Sisera. Sisera was very tired, so he was sleeping. She put the tent peg to the side of Sisera’s head and hit it with a hammer. The tent peg went through the side of his head and into the ground. Sisera died.
Judges 4: 18 - 21 ERV
Most blessed of women is Jael,
The wife of Heber the Kenite;
Most blessed is she of women in the tent.
Judges 5: 24 AMP

That's exactly where Jael was.
But God.
Jael was exactly where God wanted her to be, spiritually, mentally, and physically. Dear Reader, it only takes God plus one to make a tremendous difference in the lives of many.
“So let all Your enemies perish, O Lord;
But let those who love Him be like the rising of the sun in its might.”
And the land was at rest for forty years.
Judges 5: 31 AMP (from the Song of Deborah)