Where are you growing this tree? Indoors or out? Citrus trees can take a long time to flower and fruit when grown from seed, this tree is seed grown correct? A few things that you can do to promote fruiting sooner is to give it as much light as you can. If you can grow it outdoors, bright sunshine can help a lot with this. If indoors: some good grow lights can promote more growth. If you want to preserve node count but get more branching, using some thick wire and bending the tips of the branches towards the ground can encourage branching without pruning.