When you leave your Bitcoin on an exchange like Coinbase, you don't actually control it, since that exchange possesses the 'private keys.'

You're in a dark place right now; I don't know how much of your 'fortune' you've blindly invested so far, so I highly recommend that, for the time being, you leave things as they are and get yourself up-to-speed on learning Bitcoin. Once you've learned the basics of Bitcoin you can begin making sound decisions, i.e. moving your Bitcoin off an exchange, et cetera.

For now learn Bitcoin. A good starting point would be to get a copy of 'The Bitcoin Standard', by Saifedean Ammous - I was able to download a PDF version for free. Next, you'll want to visit the following YouTube channels:

1. Matthew Kratter - Bitcoin University

2. BTC Sessions

Take your time, learn the basics; then you'll know what you have to do regarding your Bitcoin on Coinbase - but don't take too long...there's a saying in the Bitcoin community, "not your keys, not your Bitcoin." You may not know what that means now...but you will eventually 😉