Yes you can choose between both. Homeschooling is legal in Belgium. Education is compulsory, but school attendance is not. Article 24 of the Belgian Constitution offers parents “free choice” with regard to the education of their children. Since Belgium is divided into three language-communities, further regulations on home education come from the regional level.
However, children have the option of starting school at 2,5 years old (classe d’accueil) but compulsory education only starts at 6. It is advisable to send your child to school or provide education as early as possible, because it benefits the early development of your child.