This is different from the question of "Why does Leia send Han to confront Kylo Ren instead of going herself?"
Regardless of whether Kylo Ren is on the base, and regardless of who should confront Kylo Ren, Leia is still the better person to go.
- As a force-sensitive person she could have better piloted the Millennium Falcon in the risky landing maneuver.
- She could have used the force to find Rey better than anyone else on that mission.
- She could have used the force to disable defensive systems on the base just as Obi-Wan Kenobi did on the original Death Star.
If I was a general and somebody said they would infiltrate an enemy base, you can bet your last dollar I would ask how they plan to do it. I would never blindly believe one of my employees no matter how much I trust the competence of that employee. Generals don't leave high risk missions to chance (or the force). They want to know the logistics so they can plan for contingencies in case the mission fails. They also want to know logistics so they can make sure those who go on the mission have all the equipment and support they need. To use a quote from the military - amateurs talk about strategies, experts talk about logistics. If she is in charge, she has to know the details.
- Why did she not ask Han to describe his plans?
- Why doesn't she insist that she go?