how do u say i came to ireland when i was 3 years old in french
je suis arrivé(e) en Irlande quand j'avais trois ans = I arrived in Ireland when I was three years old (the e in brackets is for if you're a girl as the passe compose under etre has to agree with gender!)
j'ai venu à l'irlande quand j'avais trois ans = I came to Ireland when I was three years old
*any corrections if I'm wrong thanks!!*
You're correct for the first sentence @O' Dwyer.
However the second one would be:
Je suis venu(e) en Irlande quand j'avais trois ans.