Not knowing a programming language before going into college shouldn’t hinder you at all with regards to entry to the course. Entry to these courses is determined by the amount of points you get from doing your leaving cert. While for Limerick, honours maths is not a requirement, I would strongly suggest you study for it, as you are going to have to be comfortable with your maths for games programming.
You seem very reluctant to move to Carlow, so why even think about it? It depends on what you want most and what compromises you are prepared to make. Why even go to Limerick? Why not try an ‘ordinary’ computer science degree at UCC and then decide what you want to do. The reason I say that, given your reluctance to move to Carlow to study, how would you feel about having to move abroad to work when you finish your game programming degree? At least with a CS degree you would have *a lot* more options to work over here (and in Munster). If you choose a CS degree, go for one with a high maths content and possibly one with a game programming module in it as well.
My advice to you would be not to worry about the post-grad option just yet. Concentrate on getting the amount of points you need for the course of your choice. If you don’t mange to attain the points that you need this time ’round, then consider repeating. Take one step at a time. Also, try and learn some programming language in your spare time and see if you like it or not. I’d recommend you start of with ‘C’ first and if you like that and get reasonably competent with it, then try C++. If you discover that programming is not for you, then simply look for a different course!!
Hope that helps.