Buff, there's nothing between your pine and a good little pine but time. Without some experience with pines it's easy to waste a lot of time. Analyze your tree, strength an weakness and develop a plan to accomplish what you want. To me I see a very young tree, no bark. I see a weak tree, not many buds after de-candling and weak one year needles. No buds close to the trunk on existing branches and reverse taper down low. The forensics of growing is the trickiest part. How do I address as many minus's with the least intrusion and get the results that are needed. Number one, strength, feed, feed, feed and feed. Black pine needs a tremendous amount of feed to develop as quickly as possible with sun from dawn til dusk. Nothing else needs to done until fall, come back then. The reverse taper at the bottom can be grown through by growing a sacrifice branch at the top. The whorl (mess) can be addressed in the fall and a sacrifice can be isolated. TIME, don't be in a hurry.
Don't be discouraged by others. Your tree is young, but the advantage to that is rapid growth and an opportunity to create your own vision for the tree. I believe bonsai is more about creating something than having nice trees in pretty pots. I'm sure with a combination of time, experience, and making educated choices this tree will look great.
I agree with garywood. Do what was recommended earlier to get as much growth as possible. Choose a leader to get rid of that mess at the top. Grow a LOW sacrifice branch (I see you already have one) and get as much root growth as possible to overcome the reverse taper.