I'm not sure how it works in Ireland, but I would imagine that the FAI rules are pretty similar to the English FA. I understand that, even at 14, you are protected by the Child Protection Laws (cite those, if they apply), and as a result, you are not deemed responsible enough (not my words) to sign a contract. Therefore, once your registration ends (assuming you were registered to the team for 1 season only) you are free to choose to play for another team.
Yes, moving to a rival team, whether it is in the same street, same league or whatever, can cause bad feeling, but it is your choice. Unless you signed something (which you legally cannot do as a 13 year old - you must have been 13 when you signed registration) there is nothing that ties you to the previous club.
If I were you, I would contact the league secretary for advise on where you stand. I am pretty sure that they will represent any child's interests before that of a club.
Failing that, yes, legal action is certainly something that could be mentioned and watch the swift change of heart!!
I've had a (very) quick look at the FAI website. There is some info on there regarding Child Welfare, etc. See if any of that applies. I'm not sure what type of football yoou play - youth or schoolboys, etc. so you will need to dig around. I think that a phone call to the league might be a good starting point. What about the team you're going to? Don't they have a Child Welfare officer?
http://www.fai.ie/index.php?option=com_c...&Itemid=98