Any anime/manga with love triangle, where the female lead chooses the other guy in the love triangle and then realizes she's made a mistake by not choosing the main guy? Like she likes the other guy at first, but then realizes she loves the main guy instead.

Like in Watashi ni xx Shinasai!

Yukina (female lead) chooses Akira (other guy) over Shigure (male lead), but then realizes later on that she made a mistake and she loves Shigure.

Hana Yori Dango - Even though she did have feelings for Rei and chose him at first, Makino was tore up inside over Tsukasa who she was in love with from the start.

Quote from SangMo

Hana Yori Dango - Even though she did have feelings for Rei and chose him at first, Makino was tore up inside over Tsukasa who she was in love with from the start.

I've read this, but thanks for the suggestion.

I've only seen the anime a loooong time ago but maybe "Peach Girl"
If I remember correctly Hirunaka no Ryusei might fit the description
I'll come back later if I have other ideas 😁

Edit : There's a little twist from what you want but I think you might like "Orange" (I believe it's a Manga from Takano ichigo, not sure tho)

This happened in Ao Haru Ride.

And, although not yet fully scanlated nor has it been updated in ages, Principal also exhibits this quality.

Oh, and there's also a webtoon called Our Relationship Is... which incorporates this as well.

Quote from AA-A-AA

This happened in Ao Haru Ride.

And, although not yet fully scanlated nor has it been updated in ages, Principal also exhibits this quality.

Oh, and there's also a webtoon called Our Relationship Is... which incorporates this as well.

Thanks. I'll check them out.

There's also For the Sake of Dulcinea, but I warn you, it's rather sad(And she takes forever to realize her true feelings)

Quote from Rosepedal43

There's also For the Sake of Dulcinea, but I warn you, it's rather sad(And she takes forever to realize her true feelings)

I've read it. Man, was the main girl fickle.