Hello.
I am 14.5 years old, weighing 60 kg (135 lbs) and I am currently using my electric bikes for my commutes, which are from 4-7 km long rides, a total of typically 15-20 km a day.
I wanted to switch to bike without a motor, and I have a few questions:

1. I dont want to get sweaty, since I'd be riding to school. I can I do that?
2. I do a lot of sports, including 6 hours of surfing in some days. does the cycling take a lot of energy?
3. What type of bike should I buy, considering mostly road and sidewalk terrain, and how much should I invest and how would it make difference ?

Thanks a lot!