Does it make sense for young investors to be buying an S&P 500 ETF right now?

I’ve been investing for many years and, like most people, I’ve had both wins and losses. There are still plenty of things I don’t fully understand myself.Recently, my child told me that after watching me trade stocks over the years, he’s become interested in investing and wants to try getting started. Individual stocks feel too difficult and risky for him, so I suggested beginning with an S&P 500 ETF. My concern is that the S&P 500 is already near all-time highs, and I’m not sure whether this is the right advice. Am I thinking about this the right way? Do you have any recommendations?