For a start, read our guide on education and schools in Ireland. There are, of course, differences in the school systems of Ireland and America, and a period of transition will be normal for any child.
Your youngest will probably adapt quickly (kids are remarkably resilient), but if you're concerned about your teenager, have you considered international schools? The IB program is internationally acclaimed, and international schools generally provide a smooth transition for expat children. Some also offer the American curriculum.
Hope this helps,
I am also from Boston and will be moving to Louth in December 2019 with my Irish husband and our 14-year-old. We are planning to be in the Carlingford area. I would love to hear where you ended up and how your children are getting on.