From the stalk it seems the plant has aged well, however the branches seems to be young. The middle branch looks relatively older than other two. It is good as well as bad that all the branches are presently bearing fruits. Fruits at the tender branches are a sign of a matured plant, however it also indicates that it will take more time for that branch to mature.
It can be an emotional challenge to prune branches with fruits. However, if you can overcome it, target two branches that are relatively newer and trim them to their half length. Best would have been to remove the flowers when they appeared. Don't prune it completely, trim it to half length. New lateral branches will arise from it and eventually help the plant to be denser.
Let the tree get matured first before allowing it to bear any fruits. In the near future remove any flowers, if they appear until the plants takes a denser and sturdier shape.
Hope this is helpful. All the best!