From the Type Certificate Data Sheet
"Life limitations are provided in the A319/A320/A321 Maintenance Planning Document, Section 9 “Airworthiness
Limitation Section”, Sub-Sections 9-1-2 and 9-1-3 - Approved by DGAC.
"I know one of our aircraft has logged around 12000 hours of engine life and got replaced with new engines ( 2 engines ).is this normal "
If you also look in the AMM Chapter 5 Limits you might find the relevant data for engine life limited parts, otherwise check with your maintenance program/planning group or local Airbus rep.
Hope this helps....