Learn Spanish (Latin America): Ojalá no hubiéramos desperdiciado la juventud.

Using ojalá with the past perfect subjunctive expresses a regret about an action in the past, meaning 'I wish we had not done it' (but we did). If you used the imperfect subjunctive (ojalá no desperdiciáramos), it would change the meaning to a present or future wish: 'I hope we do not waste our youth.'

Why does hubiéramos have an accent mark?

In the imperfect subjunctive, the nosotros form always has an accent mark on the vowel right before the -ramos ending. This keeps the spoken stress on the correct syllable. Without the accent, the rules of Spanish pronunciation would force the stress onto the ra, which is incorrect.

Why does the Spanish sentence use la juventud (the youth) when the English translation says 'our youth'?

Spanish often uses definite articles like la instead of possessive adjectives like nuestra when the owner is already obvious from the context. Because the verb hubiéramos is in the 'we' form, it is already perfectly clear whose youth is being discussed.

Can I put the no between hubiéramos and desperdiciado?