There's nothing stopping you from dipping your toe into the study before you start the course. Get the list of study books from Sam at HAI and maybe order them from Amazon. Have a go at learning Meteorology, get some question banks and test yourself, then when you learn the next chapter go back and test yourself on the previous as well. Not only will you be pre-empting a little of the strain later on during the ground school, when you've got all the other subjects to learn as well, but you'll be retraining your mind into how to learn.
(Plus meteorology is something you can practice on a daily basis, decoding METARs, observing the fronts and weather formation, etc.)
Si