I have an Avocado plant that is a bit more than a year old.
It resisted trough winter, even if I feel like it need more moisture in the air (it's been pretty dry here recently).
Anyway, most of the winter went trough, and I got told to prune it by spring, cause it's pretty high and thin, and would like to make it more low and wide.
What would be the best way, should I just cut it from half (it is 30 cm long atm).? is it a risky operation and the plant might die from it ?
I think your concern about cutting it half-way up is valid as this would leave it without any leaves with which to photosynthesize. While you might get away with that in an older, established tree, I wouldn't imagine this has enough energy stored to grow new branches yet.
A better course would be to snip it just below the highest set of leaves. This will trigger branching lower down. Once those lower branches are established, you can prune anything above them with little concern. Keep an eye on it though, as those lateral branches can get really long and droopy. You'll need to prune those at your preferred length, too, eventually. Ideally you'd move it outside for the summer - making sure to acclimatize it to full sun over a period of a couple of weeks. My father used to burn off all the leaves of his avocados every spring when he put them out in full sun in late June with no transition. They always recovered, but who knows how much it set them back.
