Diana,

Actually, in Ireland, you are better off driving a smaller car on the little roads. When you pick it up just be sure it is in good working order. Ask for a current year car.  Also check the tires for tread and the windshield and windows for chips because most insurance does not cover them. Make note of any defect, scratch, dent, scrape, etc. on your car rental form. Before renting check my car rental page for tips.

Michele