Most people who emigrated were illiterate and undocumented. They didn't know how to spell their names and hadn't a clue as to what age they were. At the port of arrival their names were recorded phonetically, their ages were only guessed, and this is the information that followed them for the rest of their lives.
The proof of this occured in 1909 when the old age pension was introduced into ireland. People had to prove their ages and were forced to go through baptismal records to establish when they were born. That is why there is such HUGE discrepancies between ages in the 1901 census and the 1911 census of Ireland. Dates were found to be out by many many years in some cases.
The name Kirk is quite unique in the souther Ireland. I searched www.rootsireland.ie and found two records.
Ellen Kirk, father Thomas Kirk, baptised in 1834 Co. Cork
Ellen Kirk, father Thomas Kirk, baptised in 1843 Co. Cork
This site only covers North Cork so would not include Queenstown. Are you sure she was actually born in Queenstown. Many Port of arrival records ask las place of residence and many records throw up the nearest town or city, so keep a very open mind in your research. It's free to join but would cost you approx €5 to view the records. I think it would be worth it if I were you.
The other site for south Cork is www.irishgenealogy.ie (free). I found a couple of Ellen Kirks but the father is listed as David??
Back in the old days anybody under 21 was considered a minor. She may have looked really young and not known her date of birth.
Anyway , hope this helps you a little,
One would wonder also about the name Quirke???