This question is widely asked by a majority of students after appearing for the JEE once because many of them are not able to score good . But the thing is that your decision depends on the factors that lead to your failure

I personally believe in the quote : Introspect but never repent for the past , which means you should do the diagnosis of your failure but never regret for it. So, all you need to do is to think what factors led to your failure . If you think you can handle pressure in the upcoming year because it needs huge level of courage to take a drop because you need to manage time since you have to finish the complete coarse in only one year and trust it runs very fast then you can go for a drop . But if you are backed with decent basics then you can develop great command on topics by practising because all you need is practise and time management. And if you think you are weak in 75% percent topics then trust me you should not go for a drop because you will not be able to manage it.

At the end I want to say that 1 year doesn’t matter a lot and if you want it badly you will do it, just do it but remember do manage it properly, atleast you will not regret that you haven’t tried for it. Just put your blood and sweat into it .