"Please, help me. I've been stuck in this childish body with the only form of communication being the ability to manifest these heart bubbles AND PEOPLE ARE GIVING ME EVIL LOOKS!"
That's silly, no.
Alright, anyway.
You become invincible, more agile, and can choose to become the world's first superhero or super-villain.
BUT
All your loved ones become twice as fragile, physically and mentally, and will age twice as fast.