An explanation of types of secondary education is here.... and for a 12 year old, if born in 2000, will be in the first year of secondary.
For the first year of secondary, there are 2 timetables possible, A or B. A is for most children who have done well in primary, B is a transitional year for children who have fallen behind, or who need an extra year of secondary - I know a child who did 1st B this year as although he is Flemish, he spent his primary education in the UK and the school felt he needed the extra year to perfect his written Dutch. It might be a consideration in your circumstances, you might want to look for a school which does 1A and 1B classes, to give yourself that option.
In 2nd secondary, there are a few more optional hours, on top of the compulsory Dutch, Science, Maths, Religion etc, the options are different in each school. If you know already your child has a particular talent which is offered in only a few schools, you might want to seek out those schools. Otherwise just bear in mind the options available from 2nd secondary onwards. There is a particular list of these options here.
Schools are ASO, BSO, TSO, KSO, but the definitions really only come with any importance by 3rd secondary when you choose a general academic education which is ASO, or technical (could lead to university still, specialised academic) which is TSO or professional (least academic) which is BSO. KSO is really really specialised, it covers the national ballet and arts schools, I think you'd probably know about these already if they interested you and guess entry is by audition to these schools. So ASO is the most general academic education and I am guessing you will be looking for a school offering ASO for all 6 secondary years. Some schools only do ASO, some only BSOÂ or TSO and those only start from 3rd secondary, some schools offer ASO, BSO, TSO in the same school. So although the division does not really start until 3rd secondary, it's worth trying to choose for the future in 1st secondary, to avoid having to move between 2nd and 34d secondary, like so many children indeed do, when they find out ASO type education is not suitable for them and their ASO only school has no TSO or BSO from 3rd secondary upwards.
As you're moving to Lier, your choice might be limited to the schools nearest Lier. Here are all the Lier secondaries. Under each entry are details whether 1A and/or 1B is offered, what the options are for 2nd secondary.
It looks like for Lier, you have only 4 options for a general ASO education.... 1) 1st and 2nd secondary at Anton Bergmann (only has these 2 years) and then a transfer to a school offering ASO, most likely Atheneum Arthus Vanderpoorten 2) Sint-Gumaruscollege 3) Sint Ursulalyceum 4) Rudolph Steiner (likely to have school fees).
