Is it worth it for a 17 year old to put money into the Dow Jones or S&P 500 ETF if I’m only putting an original investment of around $1500?

I want to start putting money into ETF’s and was wondering if putting this little into either of those funds would even be worth it for long term gain. I know the market only goes up basically so that’s why I want to put money into one of these. I have 5k saved up so far for college and was planning on putting some of it into these. Then an additional $500 a month into it until I quit my job and go to college. Is it worth it or should I invest in cheaper ETFS? Would love some advice from experienced investors