The use of the past participle in a verbal construction is normal Irish but sounds very old-fashioned in Gaelic. Probably because it is rarely found except in the Bible. We generally use past participles only adjectively ('it is broken/open/closed' etc. and they are consequently only found for a few verbs such as these.
Other features of Irish grammar can sound equally old-fashioned, such as Is tidsear mi.
Also I am guessing (from a limited knowledge of Irish) that agam means 'by me'. If so it would be leam in Gaelic.
In these sentences, everything I say about adjectives applies to agam even though it is not technically an adjective.
In English you can easily tell the difference between attributive adjectives that go before the noun and predicative adjectives that go after the verb, so the difference between
- My cup is broken
- The broken cup is mine (i.e. I have the broken cup)
is obvious, but in Gaelic the word order makes it much more difficult (very occasionally impossible) to tell which is which. But we can (just) tell from the word order here
- Tha an cupa agam briste
- Tha an cupa briste agam
To show how difficult this can be, Tha an cupa sean briste can mean either of
- The cup is old and broken
- The old cup is broken