good idea to do the class1 medical first up, (although you dont need it as a student pilot and even private pilot) as it will give you peace of mind that you are good to go health-wise if your heart is set on being a commercial pilot.
i would suggest limiting the number of nights out at ear-bleed-inducing night clubs
class 1 medical runs out after 1 year but you will be able to fly as a student/ppl for another 3 years under you class2 medical.
a quick google search netted this:
Civil Aviation Safety Authority - Medical certificate requirements
good luck!