OP I can't speak for Lizzie Ant, but it is very well known that most baby name sites are rubbish, factually speaking.
The website I sent you a link to is probably the most accurate www.behindthename.com/
It has an specific interest in the history of names and - as it says - it can find no evidence of Torin as an Irish first name.
The very scholarly and authoritative Oxford Dictionary of First Names (with over 6000 names listed ) www.oxfordreference.com/view/10.1093/acref/9780198610601.001.0001/acref-9780198610601 does not list Torin as a first name, either.
Yes, most names are very old, as you say, but there are traces of them in old sources - books, songs, legal records, myths and legends etc.
Almost all traditional Irish names feature in these old sources- there are websites about them, listing sources going back centuries. Torin is not among those names, so far as I know. New Irish names with a political or nature meaning (eg Saoirse) are not included in the old sources, but we know where they came from - 20th cent thoughts about politics and nature.
A quick Google does not turn up any well-known people or characters in myths etc named Torin before the 19th cent ; most were/are American. As I said yesterday, one of those was French, who used the second half of his middle name as a stage name; the other one was an early 20th cent British actor, named after his father.
That actor's father's surname was Thatcher, but his other first names were Scottish (James, Blair). And I think that gives us a clue. It is a Scottish tradition to give second sons their mother's surname as a firstname.
Ancestry.com - the massive family history website - records 4 families with the SURNAME Torin living in Central Sotland (Midlothian) in the 19th cent:
www.ancestry.co.uk/name-origin?surname=torin
If you look at the England and Wales census record on the Ancestry web-page listed above (click on the left-hand image) you will find quite a few people with the surname Torin living in England in the 19th cent. One of them is called 'Shaun' which suggests an Irish connection, but most have perfectly usual English-language names.
Spellings were not fixed until really recently, so there are also people listed with surnames Toran , Toren, Toron.....
It may be that Torin is a SURNAME of Irish origin that spread to Scotland, England and America (times of large-scale Irish emigration). Or the surname may have another origin (eg Norse - there is a Dutch surname Toren that originates from the Norse 'Thor'.). Without further investigation, it's impossible to say.