It sounds like the LLC had not "intended to be classified as an S corporation" for 2024. If that is the case, it does not qualify for the late election for 2024. The S-election would need to start in 2025.
However, you may want to make sure you know the pros and cons of the S-election. Many people don't fully think it through and the S-election may not be in your best interest.
https://www.irs.gov/instructions/i2553#idm[phone number removed]128
