The reasons I haven't, really, yet, are (a) the last three months have been something of a "purple patch" for me anyway,
Last three months are fabulous, we have every now and then periods like this that profits can be huge, but volatility too. But I think it is no problem for you to handle that in a safe way.
Just pay attention if for you 2016/17 was not so good in the ES. Last three months were exceptional, not normal. So if you need this type of market (last three months) you might be disappointed because this cannot continue.
Would not advice newbies to start at this moment in the ES.