I looked over your translation and have given it a rating and my reason for it:
First, I'd like to point out that 'forbidden' could have been used instead of 'prohibited', as I believe the word is too literal and using forbidden will not lose the meaning of the original.
if you permit me I give you my life > If you'll allow it, I'll give you my life today
Tú eres todo para mí > you are everything to me
you came once rather only happy > You were once just a friend
we knew,prohibited love > we got to know each other1, forbidden love
ajena to me,an angel of course > I found you strange, maybe you were an angel
but rendido destiny fell > but fate/destiny surrendered
my eyes died for you > my eyes would die for you
you will not worry about me > you didn't belong to me
Eras todo para mí y hoy me entrego a tí > you were everything to me and today I surrender2 to you
stop seeing and come to me > let yourself be seen and come closer to me
because3 you deny it if you wish for me > why do you deny it if you desire me
seems a lot more simpler-that is if this is okay(both parts)