Q.avocado plant
I started an avocado from the pit, but the stem was 8 inches tall before it got any leaves, and other than a few teeny ones along the stem, all of the leaves are on top. Should I cut off the top of the stem and hope that the teeny ones start to branch out? It’s now over 13 in tall and I’m afraid I’ve messed it up, even though it looks very healthy.
Your plant is spindly and likely due to not enough sunlight.
Yes, you can pinch the top growth to encourage a busier plant, though it will not grow leaves on the lower part of the branch.
It actually looks like a topiary and I thinks it's pretty!
https://www.gardeningknowhow.com/edible/fruits/avocado/indoor-avocado-plant-care.htm