Yes it's OK to eat guava seeds.
The seeds inside Guava fruit are edible and actually healthy for you and also have fiber in them.
The guava fruit itself also contains fiber as well as many other vitamins, nutrients and minerals that are also all good for optimal health.
But the guava seeds also contain all those vitamins, nutrients, minerals and fiber as well.
So you're getting more health benefits by eating the guava seeds along with eating the guava fruit itself.
I like to chew the guava seeds as a snack after eating the guava fruit.
You can also swallow the guava seeds whole if you prefer to eat them that way instead of chewing them.