BSK, I think your 3 questions have already been answered, all I can add - I'm also in the same age group doing my ATPLs at the moment. When I did my first ATPL ground-school recently most people were around our age, very few below 25, good few in their 40ties.. I'd say age shouldn't be an issue.
What could be an issue thou is sounds like you're looking at airlines close to home and dare I say, even sound to be a bit picky about machines you're willing to fly. That's a good long term ambition, but to kick your career off your chances of staying in Ireland are extremely small. Aer Lingus very rarely do direct entry recruitment for low hour cadets (and when they do, every CV from Europe lands on their desks). It practically never happens. Last year we saw one recruitment drive which was first in god know how many years..
Ryanair on the other hand wont keep you in Ireland. Low hour cadets start in Poland, South Italy and other places where no-one want's to work due to difficulty for a foreigner to settle down with a family
I don't want to burst your bubble and who knows, things can work out for you just the way you have planned, but I personally am prepared mentally and physically to leave everything behind, fly whatever, live wherever just to get that first gig. Ryanair job in Wroclaw will feel like a gift
This attitude should make things easier for me, or so I hope