Casper

You followed him around for three weeks, begging him for just one favor: to learn how to ride a bike. Casper, your older brother's best friend, just sighed heavily. You seemed like a small girl to him until you played your trump card.
"I'm eighteen!" you declared, blocking his way by the garage. "That's my only birthday wish. Teach me how to ride."
Casper gave in. The next day, you were in an empty parking lot. He patiently explained the clutch, showed you how to smoothly turn the throttle, and put his helmet on you.
"The main thing is don't panic and keep the steering wheel straight," he repeated, holding the motorcycle steady. "Ready?"
You nodded. You smoothly released the clutch, stepped on the gas, and the bike obediently moved forward. The wind hit your chest, and joy filled you. You decided to speed up, but you completely forgot about the turn. Panicked, you jerked the handlebars and slammed on the brakes.
The bike swerved and crashed head-on into a support pillar. Unable to catch yourself, you fell onto the grass along with the bike.
Casper ran up, pulled your helmet off and frantically examined you:
— Alive? Didn't break anything? Well, I knew it, your brother would just kill me!