Do you know why you have such hesitance about skiing a wider ski? Are you worried they are going to be more difficult to ski, or you've just never skied one before? Based on my experience of buying my first "powder" ski (I put powder in quotes because they were 102mm underfoot and not even really considered a powder ski (Sheeva 10), more an all-mountain ski that can handle powder), I think the only way you will shock yourself with a wider ski is how much easier they make it to ski powder, haha.
I have noticed lots of hesitance among fellow lady skiers to get a wider powder ski. They make skiing powder way more fun, why not? Instead of spending your time on powder days worried you're going to bury a tip, and skiing backseat to prevent that from happening, which then leaves you exhausted and working way harder than you need to (don't ask how I'm so familiar with this scenario
) , you can actually trust your skis, which empowers you to ski with more speed/momentum/flow and stay forward. Then you can actually focus on what matters like working on your powder turns and technique.
When you mention turning too sharply and ending up on your side, that sounds like you're maybe letting your shoulders and upper body follow your skis, and the over rotation is causing you to spin out and crash. I was having similar troubles with my powder turns until I worked on keeping my upper body quiet and forward, and wider powder skis (110mm underfoot) enabled me to trust that I could keep myself forward without my ski hooking up or diving into the snow.
One of my skiing goals was to actually be able to enjoy powder days (they used to be such a struggle!) and I am super stoked that I'm finally there. I want more women to be able to enjoy them too, instead of pow days just being a sausage-fest of dumb testosterone frenetic energy, lol.