You will want to make sure that the topgrowth doesn't get overpowering and shade the lower growths significantly. When this happens, the plant will naturally shut down the shaded branches, and they will die off. You will probably find that the top of the plant will always want to grow more vigorously, and you will need to shorten and thin the growth out to allow sun to reach lower foliage. This will encourage the lower branches to be as healthy as the upper ones and bloom just as well, too.
I would still completely remove one of the three hefty top branches. The odd branching configuration will still become more noticeable in time. And it looks as though the topmost growths are already on there way to dominating over the lower branches. You will probably want to cut them back, even as much as half their length.
