I agree entirely. My father always said this to me when I was younger. I would always be concerned with how much his new TV cost or how much the new car set him back or how much he was earning (whilst I was in my teens).
He always said 'Money doesn't make you happy'. I listened but I never really understood. Until he died 2 years ago leaving me a life changing amount of money, not loads but enough to get me on the property ladder just outside London almost mortgage free. I'd give it all to still have him here
I don't know if it differs when it's money you've earned but I can't see it being much different other than you'd have a sense of satisfaction and achievement for a short while.
When you eventually realise that there's only so much low level happiness to be gained from material possessions you'll appreciate the prospect of sharing your life with someone, having kids and eventually your own family.
This coming from someone who's 21. I know the value of money. I know the value of happiness. If I could be loaded and alone or have a family and live comfortably I'd take the latter every time.
I see no attraction in having loads of money and lots of nice things if you have no one to share them with. That's just me. Each to our own. Some of us that work hard and/or are fortunate enough, have both .