There are generally two kinds of undergraduate thesis defense: college defense and school defense (some undergraduate colleges are college defense, and they are completed in groups, depending on whether your school rules can keep up with the fashion). Some schools have school-level defense, and school-level defense generally draws lots to produce a list. You are very lucky.
Whether it is a school-level defense or a college-level defense, you can basically pass your own defense. The defense at the school level will feel wider, and the defense at the college level will ask deeper. But if the school defense meets a teacher with the same research direction as your thesis, then ask for more happiness.