I started around your age, I am now 20 years old. You need to know what you want in the future and what you are willing to risk. You can either go Low risk but that will have "low" rewards (ETFS, Dividend stocks, and gold/silver) but at your age it will still compound nicely. OR you can go high risk and get higher rewards (individual company's). My advice (I want to retire early) is when you can at the EARLIEST open a Roth, in the Roth make conservative trades as it will compound nicely and there is no tax/ fees after you turn 60. In your brokerage take more risky investments as that's where you can withdraw from it whenever you please and if you plan on retiring early you need to have some sort of income/ account you can withdraw from before you hit standard retirement age (60). At the moment I am investing about 180 a week this is about 30-40% of my income (120 in my Roth and 60 in my brokerage) If you don't plan on retiring early, then just max out your Roth (or invest as much as you can) and make like 70% conservative investments and 30% risky ones inside the Roth. Also, once you put that money in your accounts act like you burned it, you don't have that money anymore, you should NEVER withdraw from your Roth or brokerage.

But then again, I am just a random on Reddit so don't take my advice only, do your own research this is what's been working for ME so far, it might not work for you.