Essentially, you're trying to find out if age does (or does not) supersede service; they are exclusive requirements. You must satisfy a service requirement, and satisfy an age requirement - in any order. Age is not more important than service, so your service prior to an age requirement still counts. Otherwise, if a plan had the most strict requirements no one could be a participant before age 22 (Age 21 + 1 year of service).
Vesting should be clarified in the document, but I don't believe you can exclude years "Prior to participation.