I've now had two friends who actually started menopause in their 30's... While not typical, it is possible.
They both spent over a year experiencing unexplained weight gain, hormonal swings, and a bunch of other symptoms that sent them to multiple clinicians. They were poked and prodded, tested, and dismissed. They had numerous diagnoses and treatments that didn't help.
In one case it was self directed research, and in another it was a functional medicine practitioner that finally helped them gain clarity on the issues.
If you have friends or coworkers in their 30's who are having unexplained issues, share with them! It might save them months or years of struggle!