He had wanted to go to the Academy and become a Shadowhunter, to learn more about his own life and remember everything he had lost, to become someone stronger and better.
Except that you did not become someone stronger and better by only thinking about yourself.

You know, this porridge isn't at all bad," Simon said, digging in. George nodded enthusiastically, his mouth full.
Beatriz looked sad for them, and possibly sad that boys were so stupid in general. "This isn't porridge," she told them. "These are scrambled eggs."
"Oh, no," George whispered faintly, his mouth still full, his voice terribly sad. "Oh no.

Remember, children, all the stories are true."
Simon tried to wrap his head around the idea that there might, somewhere in Germany, be a large bean stalk with an angry giant at the top.

Be a hero, Simon," Simon muttered bitterly, remembering the life Magnus Bane had dangled before him in their first meeting - or at least, the first one Simon could remember. "Have an adventure, Simon. How about, turn your life into one long agonizing gym class, Simon."
"Dude, you're talking to yourself again.

When He'd told his mother he wanted to go to military school so he could though up, she'd given him a strange look. (Not as strange as if he'd said he wanted to go to demon-fighting school so he could drink from the Mortal Cup, Ascend to the ranks of Shadowhunter, and just maybe get back the memories that had been stolen from him in a nearby hell dimension, but close.)

What?”
Jace was standing up now.
“When you first step off. Bend the knees right away. Otherwise you did pretty well.”
“But what about Isabelle?” Simon asked. “What do I do?”
“I have no idea,” Jace said.
“So you just came here to torture me and talk about yourself?” Simon demanded.
“Oh, Simon, Simon, Simon,” said Jace. “You may not remember, but that’s kind of our thing.”
With that, he walked away, clearly aware of the admiring glances that followed his every step.