I don’t think TSP is the best advice. If you’re planning to take any kind of teaching scholarship with a bond, go for PSC, followed by EMS and TSO, and failing which then TSP. Civil service is hierarchical and anything below PSC there is a glass ceiling. If you’ve done well academically, then why limit yourself when that’s precisely what civil service rewards. It also gives you an “out” if school life is not for you - postings to MOE HQ or secondments (though secondments now more open to everybody). Just cause you thrived as a student in a neighbourhood school doesn’t mean you can adapt to teaching in one. It will only happen if you can truly connect with the students, and most often it’s not via academics. On scholarship, only go for a lower tier option if they don’t accept you for the higher tier.

But my advice still stands. Go CS. Next time can still midcareer switch to teaching if the pull is really that strong. The other direction is not impossible - I’ve done it, but it takes a lot more effort.