I cannot give a comprehensive answer to your question, Dipak, but here's what I know:
- In Germany, depending on the school, Latin may be the first, second or third foreign language (my own experience in the 90s: Latin from 5th grade (age 10/11), French from 7th, Ancient Greek from 9th; this was at a so-called 'humanist' secondary school).
- In the UK, the situation is similar, I think - at the school I started teaching at a year ago, Latin is offered from Year 7 (around age 11) and some Greek from Year 8 (then introduced properly in Year 9); there are schools that offer Latin from Year 9, when students then take it for three years up to GCSE. A number of schools also offer it as morning, lunch-time or after-school clubs: the Classical languages are mostly offered in fee-paying schools, thus restricting access to them for many families. To strive towards greater equality, many teachers at state schools thus make a point to offer these 'privileged' subjects as much as they can.
And then there are places like St James Schools, who are involved in bringing Sanskrit back to UK schools. (I started teaching at the boys' school last summer; we're working hard to integrate Sanskrit into the Classics department and teach Latin, Greek and Sanskrit in parallel. At the boys' school, we start in Year 7 and offer Sanskrit all the way up to A Level; the girls' school start in Year 6; and Sanskrit is taught all throughout the Junior School (ages 5-10), mostly in the form of chanting and calligraphy/writing, but with quite a bit of actual grammar and vocabulary for all those who show an aptitude for it.)
- In the US, I believe, Latin is taught a) rarely pre-college (and Greek hardly at all), and b) mostly only from 9th grade (i.e. in high school); but I know e.g. Montessori schools that offer it earlier.
I hope this is helpful.
All the best,
Antonia