Yes cut it now. Take the part you cut off the top, cut it into 8 inch pieces, stick them in some pots and before you know it you'll have a couple more trees.
Also, what size pot is it in? If you want it to grow well this summer it needs a large enough pot to support root growth. If you need to put it in a larger pot, it is also better to do that now then after it has leafed out fully.
Rob