The Princess of Convenient Plot Devices, Vol. 1 (Manga)

After reincarnating into her favorite BL novel, Maki (now Octavia) has the perfect opportunity to fangirl over her favorite fictional couple, Sil and Prince Sirius, in real life--except she's Sirius's sister?! If that isn't awkward enough, she's expected to give up her firstborn child to be their heir! But the new Octavia won't settle for a political marriage just to produce a baby. Her brother overcame many obstacles to be with the man of his dreams, and Octavia is prepared to do the same! Of course, she actually has to find a guy first...