@bitter to the bone , you need to know which pension plan you are in. Your shop steward or a knowledgeable coworker should be able to help you with that. Or a call to your business agent at your local. There is probably even some info at upsers(.)com
If you are in the the "UPS Part-time Pension Plan" (company plan), see Article 34 Section 1(i) in the National Master Agreement. It lists '25 yrs at any age', '25 yrs at age 60', '30 yrs at any age', and '35 yrs at any age'. The dollar amounts shown there are for an older, lower accrual (payout) rate. Those are years of "Credited Service", which is defined in that Article.
If you are in a Teamster plan, check your contract Supplement or Rider for basic info.
Either way, it would be best to contact the pension plan itself. Ask for a statement/summary.