This is about the TV show "Normal People", which is an adaptation of the novel, by the same name. The answer to my question isn't clear from the TV show, but may be mentioned in the novel; either source is acceptable, presuming they don't significantly differ.
Marianne attends high-school with Connell. It's made clear from the outset that Connell is from a lower socioeconomic background. It therefore stands to reason that the school they attend in Sligo is a public school.
On the other hand:
Marianne's family is very wealthy; not only do they have a big, country house in the Sligo area, but also a flat in Dublin and a palatial villa in what looks like Tuscany. While her relationship with her mother deteriorates throughout the series, it's clear that Marianne's mother wants the best for her; at least in a material sense. Again, this is attested by her time at Trinity, where Marianne seemingly faces no financial hardship whatsoever.
While I'm not familiar with the schooling system of Ireland, comments made by Marianne's cohort at Trinity imply that it's not dissimilar to that of the United Kingdom (which I am familiar with): That is, private schools are a thing, that come with some air of "prestige". Not necessarily a better education, but perhaps better facilities, or better connections, etc., which often facilitate the enrolment to top-tier universities. I might be oversimplifying, but they exist to satisfy the demands of (usually) wealthier people who want to give their children a competitive edge. (Whether they achieve that is not relevant to my question.)
It seems to me, therefore, that the motive, means and opportunity to enrol Marianne into private school are satisfied. Why, then, does she attend public school?
The only reasoning I can come up with is, either:
- There are no private schools in the Sligo area;
- Marianne's family have moral objections to private school.
Neither of which seem very satisfying to me.