Savings vs Investing

I (18m) am in my last year of school at the moment and am unsure whether I will go to college or get a job.

I've been saving what I get from my job incase I decide to go to college and recently reached 7k saved.

College in my country is only 2.5k per year so I was considering starting to invest most of the money from my job rather than just keep saving it.

I have 7k in a normal savings account with extremely low intrest (no good savings account options in my country) 2k in the S&P 500 and 1k cash. I was considering investing that 1k and 75% of future earnings ?

Is that stupid and should I just save as im uncertain at what ill do, what do you think ?