Yeah you are right, but the character is confirmed bi in the manga, i don't think the author has ever had the intention to write her as a lesbian, but i liked where the author was going because i though it could be good rep

She did never feel romantic involved with a boy because she was in love with another person. Even her husband makes clear that she is in fact bisexual

That Araki puts his passions and love in jojo and you can really feel it, other than that creativity