Reincarnated as male lead's spoiled sis

"Ugh!!!"
I slammed headfirst onto the bed, frustrated.
"Hmmmhmmm...."
I rolled over to my back as I heard the giggles.
"It's not funny, Millie!"
Millie was Princess Lillian's attendant and while she was quiet and shy at first, Millie soon became a fast friend.
"Apologies, my lady, but I have run you a hot bath. You should get to it before the water becomes cold."
She bowed her head with a curtsy but the twinkle in her eye was more mischievous than sincere.
I huffed and got out of the bed
"Alright."
Millie began undressing me as my head filled with the day's events. Something was still bothering me.
"Millie?"
"Hmmm?"
She hummed a reply.
"Have you heard? The King and Queen are enrolling me into the Academy."
Millie nodded.
"I heard from the maids. Congratulations, Your Highness. The Academy is very prestigious and highly sought after."
I frowned and turned towards her
"But I don't have any magical ability."
Millie pondered for a moment.
"Well, it's true that when you were born the Kingdom Scholar did not detect any presence of magic. However...."
She hesitated, unsure how to continue. I was intrigued. I sat at the edge of my seat in anticipation.
"Go on...."
Millie bit her lip but seemed to have made a decision.
"You would have found out eventually but lately you have been giving off a strong magical presence."
"What?"
I furrowed my eyebrows in confusion.
"Is that even possible? To suddenly gain magic one day?"
Millie looked around nervously. I suddenly felt bad for the position I put her in, but it was too late I was intrigued and needed to understand more.
"It's not common but I have heard stories of people gaining or manifesting secret abilities later in life."
"Secret abilities?"
I frowned. What did all of this mean? I hadn't noticed Millie somehow wrangled me into the bath and was now shampooing my hair.
"Millie, when you said I have a strong magical presence...."
"Right," she nodded. "The knights, the maids and even the King can sense it. It feels like some strange aura."
Stange aura? Could this be the result of my reincarnation?
"I can't be sure of course that's why the Academy is sending a Scholar over to test your abilities. If you pass, you will officially be enrolled in the Academy. Isn't that exciting?"
Exciting was not the word I would use to describe this situation. My mind wandered back to my past life.

"Lillian, ah?"
Dani whose face had practically lit up when I mentioned I was finally reading the manga series she recommended suddenly had a deep frown set across her face. She furrowed her eyebrows in deep thought.
"There isn't much to say about her. She later plays a bigger part in the plot where the female lead tries to gain her favour, but she was easily won over with sweets. She's just a spoiled princess."
Dani had said simply with a shrug.
"Oh yeah, the prince is super protective of her because she's magicless."
Yup, all Dani said was that Princess Lillian was spoiled, magicless and had a sweet tooth. And now, one of the three things Dani mentioned was not even true anymore.
Ahhhh! Thanks so much, Dani! If I ever see her again, I will kill her!