I don't know if it's been stated as fact in this thread already - but she must have a minimum of a C3 in Honours Irish to be accepted to any of the Primary teaching postgrad courses.. And yes the "extra work" that shows an interest and a focus in teaching does make her application more favourable.
Also, be aware that there is an initiative to promote males into Primary teaching - which, if succesful will make things even more competitive...
I would plan in the future to have this as an ideal plan A, but have an equally desirable Plan B and C also - be it to do a H Dip in Education so she can become a Secondary School teacher OR going abroad to get the Primary teaching OR a different career path altogether...
Either way, she's going to College - without a doubt this best time of anyones life, don't have her worrying too much about 3 years time (thats a parents job)... There's friends to be made, J1s for travelling, foreign students with their own perspective on life - College is only 3 years... You can worry about career and work for the next 50 yerars!