Index funds, like VTI or VTSAX, that track the total stock market, or a broad section of it, provide diversification. By diversifying your investments, this decreases the level of risk in your portfolio.
This is enough money to buy a few shares of many popular index funds or individual stocks. If you choose to focus on investing in growth stocks, create a portfolio with a few shares of several of your favorite stocks, rather than spending it all on one stock.
To invest as a minor, you will need a trusted adult to set up an UGMA account, such as Acorns Early, or an UTMA account. The money in these custodial accounts belongs to you, but the adult will oversee any trades you want to do.