Of course it's not by her choice, she's still under Aizen's hypnotic suggestion.
Anyway, she'll now release Aizen and in the chaos afterwards Ichigo will get killed.
Ichigo's death will snap her out of Aizen's control and she'll realise what she's done.
She'll fall into massive despair causing her powers will fully mature.
Her powers now allow her to turn back time....but she is not in control of how far she turns the clock back.
She travels back, aiming for the beginning of the series, pre Rukia when she was at her happiest but overshoots by 17 years.
When she wakes up she has no memories of anything. She doesn't even know who she is.
WHEN SUDDENLY HOLLOW ATTACK.
She runs away but suddenly feels a nostalgic spiritual pressure. A crescent shaped attack takes out the hollow and Orihime is safe.
Her rescuer none other than a young Isshin Kurosaki.
She tells him that she's lost all of her memories and he promises to look after her until she regains them
During their time together they slowly bust surely fall in love.
They then go on to have 3 kids, named Ichigo, Karin and Yuzu.