I had a lot to learn about Ireland. I soon realized Ireland, the island, is divided in two. Check the map. Ireland is composed of Northern Ireland, which is part of the United Kingdom and the Republic of Ireland which is independent of the U.K. If you say only “Ireland” then most of the population in Northern Ireland or the Republic of Ireland thinks you mean the Republic of Ireland – the big dark green part.
Maybe you didn’t know but the Republic of Ireland was neutral during World War 2 though many Irish did join the allied forces.
If you plan to visit Ireland or Northern Ireland its best to understand a bit about Irish history before you say anything stupid. We tried not to let our ignorance show but I occasionally said “Ireland” when I meant Northern Ireland. Carrickfergus is near Belfast in Northern Ireland.