A book talking about deep philosophical ideas but I am 15

I want to read about something a bit more difficult, something that I can learn from and think about, but not too difficult. I tried to read from the author Daniel Kaufmann (I believe) and another book “Thus spoke Zarathustra” by Friedrich Nietzsche, but I barely got through twenty pages, as it was too much to grasp for me.

The topic that I am searching for is as I mentioned, something that’ll make me think, something valuable I can learn. Maybe some philosophical idea, something about habits or anything.

I would be thankful for any recomendations, that can “fit my level”, as a teen.

by Worth-Mention3507