It’ll be fine as long as it’s the right size frame. You’ll want to swap to a ladies saddle and you may also want to consider narrower handlebars and possibly a shorter stem 👍
Have a test ride and see how you find the the reach on the brake levers and getting enough power to stop the bike from speed. If it’s difficult, you can add secondary brake levers on the handlebars which will be like braking on your flatbar bike
what model Allez is it? What size is it and how tall are you?
Have you ridden it?
I’m a tall woman and all my roadbikes are ‘mens’ frames but I have to make all the adjustments above