$ 100 is enough to learn to trade but it is not easy for a beginner you will find a loss, but don't give up and continue to learn from previous experience, analysis first before buying a coin is the key.
You are right that if you do not analyze the market well if you do not have any knowledge about the market there will be a risk no matter how many dollars we start with. This is why you need to know the market first and move forward by trying to learn the trading rules. If traders can master the trading strategies they will easily make a profit and will be able to start with less than 100 and do more.