There is nothing wrong with using chart analysis to make predictions, but I dont recommend that you buy or sell Ethereum just because of how a chart looked! Just trade safe, crypto is tricky.
Chart is used to analyze the price movement, especially its history, it's helpful but we cannot just rely on it.
We also have to consider its fundamentals, the present news, and the speculation, lots of things really to consider and every trader might have a unique way of making determining its prediction. But actually in general, Ethereum is a good project, yes, crypto is tricky but we have to play the game right to win.