I'll just add my .02.
Being stable on the surface can seem important when you first start out but a properly trimmed, properly selected back-inflate works also. I use a 60/40 weighting - it floats me almost dead vertical at the surface. Yet I can easily roll forward or onto my back as needed. I'm also pretty tall so that may be a factor worth mentioning.
Logically your instructor probably stressed horizontal trim while diving and streamlining as important concepts. Having all the air on your back definitely helps your trim - streamlining with either is debatable. From my personal experience - I shoot video on almost every dive - having nothing in front is preferable for camera control.
You have slightly less stability in a jacket since the air bubble moves back to front based on your orientation. Some jacket designs even mention "channeling the air" or having other internal bladder sections - yet no back-inflate wing does. Where do you plan to spend more time diving - underwater or on the surface? Buy the optimum thing for you based on that.
Someone - maybe tbone104 often posts a good quote - "Buy your second BC first". I think that's very good advice.
All the ladies in my group (6) plus friends/acquaintances own all their gear. All of them have gone to a back-inflate design either initially or from a jacket. Only one switched back to her jacket for vanity - her jacket had more
pink on it than her back-inflate and that's the most important thing to her since all her gear is. We certainly don't have a problem spotting her on dives - or from the boat either...lol.
In addition to Scubapro and Aqualung,
Zeagle makes a line of modular womens models in both back-inflate and now also a jacket line. In the back-inflate line all are modular using their Perfect Fit System - i.e. you can select/swap x-small shoulders, shoulder straps etc. as needed.
Being small there's also soft backplate designs like the Aqualung
Zuma - a lighter weight travel focused version. Weighs less, packs small and comes in an XXS ladies model - which largely seems to be pink trim. Relatively unencumbered front with plenty of lift and supplied/optional trim weight pockets depending on which version you choose. It also has a large fold-down pocket for stuff. And rolls up into a supplied drawstring bag for travel.