And don't tighten a seat binder bolt too tight on a carbon seatpost.
Carbon is wonderful stuff (according to those trying to sell it !) as it's light, strong, reduces vibration, etc
But it tends only to be strong in whatever direction the sheets of carbon are laid, and pretty weak in other directions.
Relevant here for tubes like seatposts or fork steerers, where it's not strong at all against you crimping it by overtightning the clamp bolt.
Seen some eye-watering posts on bike forums by people saying that if you overtighten a carbon seatpin it'll crack, then suddenly snap leaving a jagged end, whereas if you overtightened alu or steel you'd just put a dent in it.
Re women's fit : really cheap bikes would just have a woman on a smaller bike, more expensive manufacturers make 'women-specific' bikes. Confusingly, other manufacturers make their small sizes in women's fit and bigger ones for men, but don't say so !
'Women's fit' works (roughly!) on the idea that women have shorter bodies and longer legs than a man of the same height, so a woman would need a bike which was shorter from back-to-front, not just 'smaller' than a man's bike. It's more complicated than that of course, as a woman would also have different length arms, shoulder width, leg strength, etc, etc than a man the same size.
So all the proportions of a 'women's fit' bike are a little bit different - not just a shorter toptube (aka 'crossbar') for the same height seattube (from saddle to pedals), but also the height of the headtube (the tube at the front of the frame that the forks fit in the bottom of), the length of the stem (horizontal bit connecting handlebars to frame), the width of the bars themselves, the angle of the forks, the length of pedal cranks, etc, etc. The wheels, brakes and gears are the same, but the geometry of the frame is all slightly different (those measurements they always quote in the blurb at the back of the brochure)
However, of course this all assumes there's a 'typical woman' just as much as a 'typical man', but no-one is quite typical and depending on your particular shape/size a woman might be better on a smaller 'mens' bike than a 'womens', or neither might fit quite right.
But that's not a problem, as so long as the basic bike frame is right, then bits like stems, saddles, pedals, etc can be swapped to make it fit you, and a good bike shop will do that for you.
To complicate further, different bike manufacturers measure their bikes from different places too, so the 'same size' frame from different makes may be a lot different in size.
And different bikes can be different styles - fast racing geometry or more comfy but slower touring geometry. This matters if you want it for racing or long rides, commuting, cross-training, etc ?
What you need is a good bike shop where they'll ask what you want the bike for, show you alternatives, let you try them, work-out what size you need, and then fit the bike to you by making adjustments or even swapping some of the bits.
Not easy, not quick, but this is what you pay for by buying from a bike shop rather than paying less by mail order or internet.
However if you feel that a bike shop isn't willing to spend this time on you and wants to make a quick sale, or just plain doesn't know what they're doing, then try somewhere else.