My avocado plant has Brown Spot!

[Plantguy]

I don’t know why but my avocado tree, which I’ve had for 2 years, got Brown Spot. I don’t want to lose it cause Ive grown it myself. I did everything I can. I pruned it, fertilized it, watered it, and put in in a spot with more sunlight. Here’s pictures. I also think I should mention that it’s young. it’s not even a 1/4 into adulthood yet.

 

[Plantguy]

Side note, I tried to check for root rot, and the seeds broke in half. I put it back together. I dont know if that’s good. i Know it sounds like I’m a rookie plant keeper, but I’m not.