Validation Rule to "Lock Up" UTM Fields on Opportunity when the Opportunity is created [duplicate]

Question

I am trying to lock the UTM fields on an opportunity when it is created. I would the field to not be able to be edited by anyone (including Marketo Sync User) other than a system admin after the opportunity is created

here is what I have so far:

AND(
$Profile.Name <>  "System Administrator",
OR(
AND(
ISCHANGED( Last_Lead_Source__c ),
NOT(ISBLANK(PRIORVALUE( Last_Lead_Source__c )))
),
AND(
ISCHANGED( Last_Lead_Medium__c ),
NOT(ISBLANK(PRIORVALUE( Last_Lead_Medium__c )))
),
AND(
ISCHANGED( Last_Lead_Term__c ),
NOT(ISBLANK(PRIORVALUE( Last_Lead_Term__c )))
),
AND(
ISCHANGED( Last_Lead_Campaign__c ),
NOT(ISBLANK(PRIORVALUE( Last_Lead_Content__c )))
),
AND(
ISCHANGED( UTM_Original_Lead_Campaign__c ),
NOT(ISBLANK(PRIORVALUE( UTM_Original_Lead_Campaign__c )))
),
AND(
ISCHANGED( UTM_Original_Lead_Content__c ),
NOT(ISBLANK(PRIORVALUE( UTM_Original_Lead_Content__c )))
),
AND(
ISCHANGED( UTM_Original_Lead_Medium__c ),
NOT(ISBLANK(PRIORVALUE( UTM_Original_Lead_Medium__c )))
),
AND(
ISCHANGED( UTM_Original_Lead_Source__c ),
NOT(ISBLANK(PRIORVALUE( UTM_Original_Lead_Source__c )))
),
AND(
ISCHANGED( UTM_Original_Lead_Term__c ),
NOT(ISBLANK(PRIORVALUE( UTM_Original_Lead_Term__c )))
)
)
)

Any help would be appreciated