If I want to put my lo to toddler class. Do I have to register now from now? Lo is 2 months old.

I guess you are referring to registering for preschool for your baby when he/she is 2 or 3 years old? A lot of my friends starts visiting centres and asking about their availability when their babies are around one. Some even started when it is near their due dates. The waiting list for popular centres could be long and they wanted to "play safe". That being said, it is really dependent on which school you are considering, as well as the location. Some areas may be more popular than others. If you are planning in advance, no harm calling the centre now (especially if it is a popular one) to find out about their "waiting list situation". Also, do go down to have a look at the place when considering the different places.