Yes, they all seem to have a mind of their own. I have one that is a couple years old and it is about 18" tall and branched at that point. Many seem to branch early on. I have chopped quite a few of my 2& 3 year old trees down and they branch out really well.
I like to leave this until the spring when I see them really starting to grow. This way when the new branches come from the nodes, they seem to produce more than apposed to when I do in the fall.
This is the nice thing about having many seedlings. You can experiment and see how it goes. I grafted some 8mth old seedling together of two different species of adenium, because I wanted to give it a go and they both took.
Rick