If thats all the tree grew last year you may just want to let it put on some more growth. Or if you want to keep it lower take off that top bit. You can prune any time, don't worry about getting it while dormant. Well, early fall is not the best time. But any other time of year you can prune. Scott

It's not too late to prune. You seem to have a good plan. Go ahead, that's the best way to learn. The Fruitnut

Yes, pruning now would remove the flower buds for next years flowers. There is also the possibility that resulting new growth may not have time to ripen before your first frost, although that would not be a danger here in my milder climate. (my milder climate where we've been socked in with fog since Saturday - Arghhhhhh!) Better would be to wait until after they have bloomed in Spring (or even during if you wish, fill those vases indoors), although you could probably get away with removing the worst offending branches if there are stems that are actually in the way. In that case, you might have to re-prune those stems to remove possible winter damage in Spring.

I personally would whack it back now. That plant is one growing machine and shouldn' be the least affected.