It's amazing what you can find when you do a Search. Here is the topic from NC DOR which explains the work period length and dates, the process which qualifies as vesting, and it even has a listing of the Federal pension programs in consideration of whether it is a qualifying pension or not:

https://www.ncdor.gov/taxes-forms/withholding-tax/individual-income-tax-directives-main/directive-pd...

Read it, and especially the part titled, "Qualifying Federal Retirement Systems."

So far, her comments are too vague. That article should be helpful.