We are in Singapore for last 2 years. I put my 4yr old son for Spanish as Mandarin in school academically gets tougher and tougher. I feel academic Mandarin may be too much for him. I mean comparatively to academic Spanish. Have I taken correct decision?

i think the choice of language you want your child to learn should depend mainly on two factors: 1. if you are looking at it from a professional angle, you'll want to see the scope of that language in terms of your child's career and future prospects 2. from an interest angle, depending on if it is a language or culture that your child has an interest in and hence you want him to learn it. i think this should be your basis of selection

if you feel its an unnecessary burden on the child then it's a good idea to go for an alternative language in school i believe. as long as your child is interested in the language class you chose and is able to pick it up, all should be good :)