The Verdict: Need More Info
Every one of Portugal's youth mobility agreements starts at 18, so you will qualify by waiting. Prepare your documents and apply on or after your eighteenth birthday.
There is no version for anyone younger, with or without a parent's consent. Your age is checked on the date you apply, not when you travel.
Use the time on the slow parts: a passport with enough validity, health insurance for the whole stay, proof of funds and a criminal record certificate. Upper limits run from 30 to 35 depending on your passport, so there is no hurry once you turn 18.