If I were you I will wait for the correction and retracement of ethereum before entering and buying it because I don't want to get FOMOed and buy high. Always remember to enter and accumulate every dip not every time that it is bullish.
In order to avoid buying high, you need to know what "high" means. Is Ethereum high right now? In a sense yes, because otherwise it wouldn't be hovering around its all time high, but then it is also possible that it breaks out and goes towards four figures at full speed. Really tough to tell here and I wouldn't bet my house on neither of both possibilities. Today it looks very healthy and stable, but that could change tomorrow. Just don't go all in, buy in tranches and build up your position over time no matter which direction it takes in the short-term.