Do I need to be aware of my diet? I have recently started biking consistently: commute 2x 5km@12min from/to school + 1x 12km@22min in the evening before dinner almost everyday.

Now I started reading and viewing deeper into the "cycling diet"-thing and realized that I generally eat a lot of sugar(cookies, chocolate bars) and fat(butter) across the day and especially for dinner after a quick power-round.

My question now: Do I have to be more aware of what I am eating or is it just fine for me to eat whatever I want, like I do at the moment?

PS: I don't have any weight problems by any means (55kg@1.73m@18years)
General answer to: 'Do I have to be more aware of what I am eating or is it just fine for me to eat whatever I want...?' I'm pretty sure a doctor or nutritionist would tell you that you should eat a balanced diet, not one that is high in calories sugar and fat. I'm also sure a lot of people in this community will tell you that diet gets more important an you get older and a more sedentary lifestyle is forced on you (sitting at a desk 8+ hours a day).

If you are only doing two 5km rides a day you don't need a special diet - just a reasonably healthy one will be fine.