https://www.riai.ie/careers-in-architecture/how-to-become-an-architect - this might help.
Points very high. 622 this year for TU. Its all about supply and demand. Low number of places, high demand, high points. An interview also seems to be part of the selection process.
Personally, I would say she is too young to be deciding her future at this stage.
Having just got another child passed the Leaving Cert, I would say the broader their subject choice at Junior Cert Level, the better. My son has been a lawyer, economist, teacher and has finally decided to go down the Finance route with Accountancy in his mind at the moment. This may change as they can specialise in year 3 of his degree.
The Junior cert should be used, in my opinion, to take as broad a selection of subjects as possible. This leaves them in the best place possible, when selecting subjects for their Leaving Cert. If they don't know what they want to do when they leave school, they can take the subjects they most enjoyed from Junior Cert and sit them for their Leaving Cert. It is so much easier to study subjects you enjoy rather than muddle your way through Leaving Cert doing subjects you hate because you kept your subject selection too narrow at Junior Cert level.
I would be in favour of the idea of taking a language at least until Junior Cert.