I studied in Tamil medium till I was 15, that is until tenth standard (the transition to English medium was fraught with difficulties and the learning curve wasn't a curve, it was just a straight going all the way up).
I am glad I studied in Tamil medium though. When my English medium friends were learning about the trials and injuries of Jack and Jill (whoever they were), or an evil grandmother and her spider in a cupboard in the name of nursery rhymes, I was learning some of the most profound and essential life lessons at the tender age of four, thanks to the esteemed works of sage poet Avvaiyar.
Avvaiyar was a poet from Sanga period in Tamil literature. While some say Avvaiyar was a title bestowed upon some of the poets from this age, I prefer to think of her as one blessed wise old lady who had the uncanny ability to reduce the greatest truths so even a five year old can understand. Aathichoodi was the work we studied and it was mandatory. Besides that was the most effective way to learn the Tamil alphabet and at the same time, learn a useful lesson attached to each of the letters. So instead of A for Apple, we learnt, A for Aim to do good (aram seyya virumbu). The second letter was aa, and the corresponding nugget of wisdom was, "aaruvadhu sinam" which means learn to control your anger.
Much later I learnt that the sage was a siddha, someone who was an accomplished being or a perfected master (this usually refers to the art of kundalini yoga and its practices). I have been a great admirer of her words as they were often quoted by my mother. It seemed she always had the right thing to say to every situation in life. Her body of work needs to have explanatory notes even though they are in Tamil but they are worth reading and spending time over. You are, however, better off starting with Aathichoodi, as the lessons learnt in childhood never leave you. Here's a link I just found: http://www.aramseyavirumbu.com/
I hope the tradition of teaching Avvaiyar's Aatchichoodi to KG students is still being preserved, if not, the loss is only ours.