"I was told I should not keep it outside."

Time will tell. I would suggest keeping the plant warm and in bright-bright light.

Personally, I belive some of the most intensely fragrant flowers such as Jasmine, Gardenia, Murraya need some heat to flourish and flower.

My Stephanotis are grown year around outdoors though they are under cover which receives direct morning sun. Some years the winter weather turns a bit nasty but it seems to have very little affect on them and they do seem to flower better afterward.

Supannee

Stephanotis definitely smells better when the flowers are young and/or when it is hot weather, though they shouldn't be kept in full sun. In Zone 9 I would keep it outside for at least six months of the year.