When you say “I was young and foolish,” does that mean you were foolish because you were young?
“If I had listened to what my mother said,
I`d have been at home today,
but I was young and foolish, oh, God, let a rambler lead me astray.”
I am now old and foolish.
Not necessary.
The use of the word ‘and’ is use to addition two differents adjectifs (in that case) to qualify the subject ‘I’.
In simplier term, it could be written like these and would be correct. ‘I was young. I was foolish’.
So there’s no direct link between the two words.
Young and foolish are often assumed to go together, as are old and wise. Of course we know that’s not necessarily true, but yes, it is often assumed that younger people are generally more foolish / unwise.
Down by the Salley Gardens, W. B. Yeats
DOWN by the salley gardens my love and I did meet;
She passed the salley gardens with little snow-white feet.
She bid me take love easy, as the leaves grow on the tree;
But I, being young and foolish, with her would not agree.
In a field by the river my love and I did stand,
And on my leaning shoulder she laid her snow-white hand.
She bid me take life easy, as the grass grows on the weirs;
But I was young and foolish, and now am full of tears.
Nice poem, thanks for sharing.
Have a nice evening.
What a combination: Yeats and The Animals!
Foolish has had many different meanings throughout history, I believe it used at one point to mean innocent.
Foolish meant innocent once?
That’s interesting.
Old and foolish woman that I am I nearly gave myself a hernia looking up ‘fool and foolish’ in my huge Compact OED. I could find no link to ‘innocent/ce’.
Do you have any idea where you came across it?
It would make sense that it once meant innocent since in French innocent can also mean foolish 
Yes, it might make sense, but there is no link in the OED to it that I could find - I’d love to know for sure.
yes also when I young I was foolish but after grow up in 11 years old I became very very intelligent suddenly surprise >> that mean I have energy but don’t know how to exploitation