There is a huge difference between singlehanding
a 40 footer and a fifty footer. Let's just assume that the 50 footer has all electric
winches etc etc etc - otherwise for 100lb. person (unless they have spent all their time pumping iron), just hoisting the mainsail
is a non-starter - it simply weighs too much
The same goes for rolling in the genua or taking a couple of extra turns to taut up the genua sheets
(and yes I do know that when single-handing, you have to fall off to do these things).
So let's just assume pure physical strength for hoisting sails
or tauting sheets
is not a problem because everything is electrical
When she tries to dock
this thing and is lugging say 20-30 meters of 1 or 1 1/4 inch 3 braid around, she will have a serious problem - How much do you think 20-30 meters weigh? Not to mention 100 lbs females generally have small hands, she might not even be able to "get her hands around 30 meters".
This is not to say she can't possibly do it. I know one woman who single-hands a 54 footer and she weighs in at about 105. But she's been singlehanding
for twenty years and started on a much smaller boat. She also says that the 54 footer is actually too big for her. she tries very hard to stay away from hard weather
I with Barnakiel - if she has to ask the question, then the answer (for her) is probably "no".