I've grown this strain. At 25cm you have a good way to go yet before of I'd see any issues with height. Even at 2x size if you were flip now it'd be in the 75cm range.
Jst keep temps in a 4c window during the pre flower window to avoid any stretching. So, what I do in cold parts of the yr. I make it so the 12hrs on "comes on the coldest part of your day and vice versa. This will help keep temp steady. Also by rasing your exhaust up and down when it's hot/ cold to control temps and you should be able to judge in future what size your grow will be. Keeping in mind what your growing, as you know sativas tend to grow up, and indicas have more girt. Lots of factors. But in saying all this, it really is down to your pref. And does she have enough shoots, node growth and so on can all be controlled with defoliation and LST, HST, and topping and others.
Good Growing