Yeah definitely pregnant and about to give birth I'd say today or tomorrow.
When she starts hiding or staying very quiet in one spot near the surface, time to separate and let her do her thing. Or you can leave her as is. That's how I do to avoid stress, however some of the fry can get eaten
She does look pregnant, but that doesn't always mean anything.
I've been keeping guppies for 20 years. I can't tell by looking is a female is pregnant or how long it will be before she drops. I've had huge guppies that never dropped fry, and thin guppies that would crank out brood after brood. The only way I can predict is to know when she was hit.